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<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Computing Descriptive Metrics and Propositions in Reading Texts and Recalls</article-title>
      </title-group>
      <contrib-group>
        <aff id="aff0">
          <label>0</label>
          <institution>Kazan Federal University, Department of theory and practice of language teaching, Research laboratory 'Intellectual technologies for text management'</institution>
          ,
          <addr-line>420008, Kremlyovskaya, 18, Kazan</addr-line>
          ,
          <country country="RU">Russia</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Kazan Federal University, Laboratory of modern geoinformation and geophysical technologies, Department of mathematical statistics and information technologies</institution>
          ,
          <addr-line>420008, Kremlyovskaya, 18, Kazan</addr-line>
          ,
          <country country="RU">Russia</country>
        </aff>
        <aff id="aff2">
          <label>2</label>
          <institution>Kazan State Medical University</institution>
          ,
          <addr-line>420012, Butlerova, 49, Kazan</addr-line>
          ,
          <country country="RU">Russia</country>
        </aff>
        <aff id="aff3">
          <label>3</label>
          <institution>Linguistic research and education center</institution>
          ,
          <addr-line>420008, Kremlyovskaya, 18, Kazan</addr-line>
          ,
          <country country="RU">Russia</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2020</year>
      </pub-date>
      <fpage>0000</fpage>
      <lpage>0002</lpage>
      <abstract>
        <p>This study addresses the problem of computational techniques to perform a multi-factor text analysis aimed at assessing text metrics and the amount of information in two contrasting texts. Assessing recalls in general and estimating the scope of information reproduced in recalls in particular are equally challenging. We introduce a computational linguistic tool that measures 28 linguistic parameters enabling conventional level of language assessment. The results are indicative of the tool distinguishing two versions of the low (OT51) versus high (MR51) cohesion of the texts but not the recalls. The results also showed that ubiquitously used descriptive metrics and readability indices inappropriately distinguish between reading texts and their recalls. Overall, the research advances our understanding of the relationship between conventional (quantitative, lexical) and semantic metrics providing foundations for more effective algorithms of assessing and profiling academic texts types.</p>
      </abstract>
      <kwd-group>
        <kwd>Qualitative Analysis</kwd>
        <kwd>Descriptive Metrics</kwd>
        <kwd>Cohesion</kwd>
        <kwd>Multi-factor Text Analysis</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>Educators view instruments performing automated multi-factor text analysis of
students’ work as tools allowing to simplify a primary task of language assessment. A
good text analyzer is expected to measure a wide range of conventional (descriptive,
morphological, and lexical) and text-level (semantic) features. The latter include
measurements which assess e.g. text cohesion, narrativity, informativeness, etc.
Researchers all over the world aim at designing tools of this kind to enable users to
select appropriate texts for different categories of readers on the one hand and assess
students’ work on the other. Another challenging area of research is an educational
text pattern appropriate for certain categories of readers which can be presented as a
set of conventional and text-level features.</p>
      <p>In this paper we describe a two-stage comparative analysis of original high- and
low cohesive versions of an educational text and their recalls. The research was
designed in the following stages:</p>
      <p>Stage 1. Psycholinguistic experiment in which two groups of students read one of
the two versions of an educational text, an original, retrieved from the textbook on
Social science, or a manipulated, high-cohesion version of the same text.</p>
      <p>Stage 2. Conventional metrics analysis of the reading texts and texts of recalls
conducted with the help of the online automated text analyzer TAR.</p>
      <p>Stage 3. Text-level (semantic) analysis based on the assessment of text
propositions.
2</p>
    </sec>
    <sec id="sec-2">
      <title>Related work</title>
      <p>
        Researchers distinguish various features influencing text comprehension. Among the
validated parameters are readability indices, vocabulary knowledge, words frequency,
abstractness and lexical diversity [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ].
      </p>
      <p>
        Text readability is predominately estimated with two metrics, i.e. average word
length and average sentence length [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ]. These are the key elements of the assumed
notion of readability expected to change across grades from elementary to high
school. Flash-Kincaid Grade level measured with the two parameters is expected to
inform users of the appropriateness of the target audience for a reading text.
      </p>
      <p>Text lexical parameters which we analyze in this article include word frequency,
abstractness and lexical diversity.</p>
      <p>
        A reader's vocabulary knowledge and lexical coverage relate to the amount of
exposure the reader has received on words and as such they are viewed as good
predictors of reading comprehension [
        <xref ref-type="bibr" rid="ref3 ref4 ref5 ref6 ref7 ref8">3–8</xref>
        ]. Typically, while assessing text difficulty
researchers resort to one of the two techniques: (1) they either assess the number of
‘difficult’ words which a particular reader is unlikely to know or (2) compute ta text
for word frequency and divide it into groups of words based on their frequency. In
foreign languages studies, words are classified based on language proficiency levels
(A1-C2, CEFR) [
        <xref ref-type="bibr" rid="ref10 ref11 ref9">9–11</xref>
        ], while vocabulary of texts for native speakers is assessed with
the help of frequency lists [
        <xref ref-type="bibr" rid="ref12 ref13">12, 13</xref>
        ]. Another parameter close to the above, i.e. word
frequency is regarded as highly indicative of word difficulty and correlates with
numerous contributing factors [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ]. Klare (1968) argues that frequency of words affects
both the ease of reading and its comprehension. Frequency of words is strongly
associated with two types of ‘difficulty’: the so-called ‘perceived difficulty’ and ‘actual
difficulty’. The first refers to the formal, external view of a word, while the second is
related to users’ ability to define or select the correct definition of the word among
distracters [
        <xref ref-type="bibr" rid="ref15">15</xref>
        ]. High-frequency words are proved to be more easily perceived [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ]
and readily produced by readers [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ]. High-frequency words are both perceived and
produced more quickly and more efficiently than low-frequency words [
        <xref ref-type="bibr" rid="ref18 ref19 ref20 ref21 ref22">18–22</xref>
        ],
resulting in more efficient comprehension of the text [
        <xref ref-type="bibr" rid="ref23">23</xref>
        ].
      </p>
      <p>
        Word frequency in Russian texts is assessed with the help of the data in S. Sharoff
and O. Lyashevskaya Dictionary (2009) [
        <xref ref-type="bibr" rid="ref24">24</xref>
        ] which provides frequency ratings of
60 000 words of different types of discourse [
        <xref ref-type="bibr" rid="ref25">25</xref>
        ].
      </p>
      <p>
        Lexical diversity or Type Token Ratio is the number of types divided by tokens in
the text [
        <xref ref-type="bibr" rid="ref26">26</xref>
        ]. Type token ratio is low in case many words are repeated within one text
or corpus. A high TTR suggests that a text or a corpus uses more diverse vocabulary.
P. Baker claims that the larger is the corpus, the more likely it to have lower TTR due
to the use of high frequency grammatical forms (e.g. articles and particles) [
        <xref ref-type="bibr" rid="ref27">27</xref>
        ]. M.
Shermis et. al (2013) use TTR to assess students’ essays. The authors argue that
‘higher ratios indicate that more concepts are introduced in a given syntactic role,
whereas lower ratios mean fewer concepts’ [
        <xref ref-type="bibr" rid="ref28">28</xref>
        ].
      </p>
      <p>
        The notion of cohesion was introduced by Halliday (1976) and is viewed as a
device for connecting different parts of a text. It is achieved through lexical means,
coreference, ellipsis and conjunctions [
        <xref ref-type="bibr" rid="ref29">29</xref>
        ]. Over the last 20 years, research into text
comprehension and memorization has grown rapidly [
        <xref ref-type="bibr" rid="ref30 ref31 ref32 ref33">30-33</xref>
        ].
      </p>
      <p>
        Based on experimental data of science and narrative texts comprehension
researchers provide evidence that both college students and children face difficulties while
reading low cohesion texts [
        <xref ref-type="bibr" rid="ref34 ref35 ref36 ref37">34–37</xref>
        ]. Texts with manually increased referential
cohesion (primarily, by content word overlap) were reported by numerous researchers to
be beneficial for comprehension and reasoning processes as compared to texts with
low referential cohesion [
        <xref ref-type="bibr" rid="ref38 ref39 ref40">38–40</xref>
        ].
      </p>
      <p>
        In this article based on the semantic roles defined as semantic frames [
        <xref ref-type="bibr" rid="ref41">41</xref>
        ] we also
perform a propositional analysis of texts to compare ‘newness and givenness of
information’ in the texts of recalls. The semantic roles are used in the paper as labels
applied to the arguments of verbs to identify their roles in the events denoted by
verbs. Sets of semantic roles vary in different studies and range from specific to
general: Agent, Experiencer, Instrument, Object, Source, Goal, Location, Time, and
Path [
        <xref ref-type="bibr" rid="ref42">42</xref>
        ].
3
      </p>
    </sec>
    <sec id="sec-3">
      <title>Materials, tools and methods</title>
      <p>
        The research data collected for the study comprises two reading texts (OT51 and
MT51) described below and 65 texts of students’ recall. The total size of the texts
studied is over 7000 words. We computed the two reading texts with an automated
tool, Text Evaluator of Russian texts (TAR) [
        <xref ref-type="bibr" rid="ref43">43</xref>
        ]) designed and developed by the
authors (see below for more detailed description) to evaluate the following metrics:
1. Descriptive metrics: 1.1. words count (WC), 1.2. syllables count (SylC), 1.3.
sentences count (SC), 1.4. average sentence length (ASL), 1.5. average word length
(AWL)).
2. Flesch-Kincaid Grade Level (FKGL) [Kincaid, 1975], assessed with 2.1. Oborneva
formula [
        <xref ref-type="bibr" rid="ref44">44</xref>
        ] and 2.2. SIS formula [
        <xref ref-type="bibr" rid="ref45">45</xref>
        ].
3. Morphological features (part-of-speech count: 3.1. adjectives (Adj), 3.2. adverbs
(Adv), 3.3. pronouns (Pron), 3.4. nouns (N), and 3.5. verbs (V), 3.6. noun cases,
3.7. verb tenses.
4. Lexical features: 4.1. Type and token ration (TTR), 4.2. Word frequency (Freq.,),
4.3. Abstractness / Concreteness (A/C).
      </p>
      <p>
        The processed text data are downloadable in spreadsheets (see Table 1).
TAR, a Python-based tool estimates values of 28 features in Russian texts. Uploaded
texts are processed with MyStem.3.0, a PoS tagger, developed by Yandex [
        <xref ref-type="bibr" rid="ref46">46</xref>
        ]
which removes stop words and tags content words with the corresponding
morphological categories: noun cases and gender, verb tense forms, etc. The tool stores texts in
XML cue files as hierarchical structures in which each word is PoS-tagged (Fig. 1).
TAR is also supplied with a Stemmer and Lemmatizer, thus providing users with lists
of stems and lemmas of the uploaded texts (Fig. 2).
Text readability indices are estimated based on modified for the Russian language
FKGL formulas: 1. FKGL (O) designed by I.V. Oborneva (2006) for fiction texts:
FKGL (O) = 206.836 – (1.52 x ASL) – (65.14 x AWL). 2. FKGL (SIS) for academic
texts: FKGL (SIS) 0.36 × ASL + 5.76 × ASW − 11.97 [
        <xref ref-type="bibr" rid="ref45">45</xref>
        ].
      </p>
      <p>TAR also computes TTR, word frequency and text abstractness (see Part 4). The
number of propositions and subpropositions were manually assessed.
4</p>
    </sec>
    <sec id="sec-4">
      <title>Research design</title>
      <p>Stage 1. Psycholinguistic experiment: reading and recalling.</p>
      <p>The respondents (n 177), 5th graders, Russian natives aged 11–12, were offered to
read one of the two versions of a text: (1) an original unabridged 200-word text from
“Social Science 5” (Text OT51) or (2) a manually manipulated version of OT51
(further referred to as MT51) which contains words and ideas that overlap across the
adjacent sentences and the entire text, with explicit threads that connect parts of the
texts for the reader.</p>
      <p>
        The assessment of text comprehension was preceded by Wechsler General
Knowledge Subtest for children (WISC GK) [
        <xref ref-type="bibr" rid="ref47">47</xref>
        ] and streaming the respondents into
two sections. Of the 118 respondents participating in WISC GK we selected 65 with
the average GK index, i.e. 13–16. 34 students read and recalled the original,
unchanged version of the text retrieved from the textbook, OT51, 31 subjects read and
recalled MT51, the modified version of the original text. The subjects’ reading
comprehension was tested by recalls.
      </p>
      <p>Stage 1a. Manipulations of text OT51 included the following: sentence splitting,
adding a topic sentence, adding temporal markers and demonstrative pronouns (a–d in
Fig. 3).</p>
      <p>We increased the number of sentences from 11 (OT51), to 18 (MT51)) (see
Table 2). We also increased text cohesion by the following (see Fig. 4):
(a) adding the topic sentence: ‘This text focuses on works of art and culture’
(MT51.1) and paragraphing which involved splitting three original
paragraphs of OT51 into six paragraphs in MT51;
(b) adding a temporal marker to connect two adjacent sentences ‘In the early 18th
century, when Russia was becoming a sea power, the Master erected a festive,
cheerful church’ (OT51.3) → ‘This happened in the early 18th century, when Russia was
becoming a sea power’, ‘It was at this time that Master Nestor built a festive, cheerful
church’ (OT51.6, OT51.7);</p>
      <p>(c) adding demonstrative pronouns to specify the referents: ‘works of art (OT51.1)
→ these works of art (OT51.3), church (OT51.3) → this church’ (OT51.8));
(d) introductory ‘for example’ to exemplify the arguments;
(e) content words overlaps (CWO) and anaphoric replacements: ‘works’
(MT51.2/3), ‘Master (Nestor)’ (MT51.5/7/13), ‘church’ (MT51.8/9/10/12).</p>
      <p>The flow chart of the Text manipulations is presented in Figure 3 below.
Texts OT51 and MT51 are presented in Table 2.</p>
      <p>S-ce #
OT51.2
OT51.3</p>
      <p>OT51
The legend says that once upon
a time there lived Master Nestor,
who built an amazingly
beautiful wooden church of
Transfiguration on Kizhi island in Onega
lake without any nail at all1.</p>
      <p>In the early 18th century, when
Russia was settling in the Baltic
sea and becoming a sea power,
the Master built a 22-domed
festive, cheerful church, which
was different from any other.</p>
      <p>S-ce #
MT51.4
MT51.5
MT51.6
MT51.7
MT51.8</p>
      <p>MT51
There is such a legend.</p>
      <p>Once upon a time there lived Master
Nestor, who built an amazingly beautiful
wooden church of Transfiguration on
Kizhi island in Onega lake without any
nail at all.</p>
      <p>This happened in the early 18th century,
when Russia was becoming a sea power.</p>
      <p>It was at this time that Master Nestor
built a festive, cheerful church.</p>
      <p>This 22-domed church was different
from any other.
4.1</p>
      <sec id="sec-4-1">
        <title>The parameters assessed and computed for OT51 and MT51</title>
        <p>Stage 2. Conventional metrics analysis of the reading texts and texts of recalls
conducted with the help of the online automated text analyzer TAR.</p>
        <p>Elaboration of OT51 comprised extension of its length (211 words → 224 words),
which manifests itself in more nouns (62 → 71) and verbs (43 → 46). The number of
1 The original Russian text was translated into English by the authors of the article. In translation we mostly
aimed at word for word translation to demonstrate the performed syntactic and lexical manipulations.
sentences rose from 11 in OT51 to 18 in MT51, which caused a dramatic decrease in
a number of words per sentence: from 17,42 in OT51 to 12.33 in MT51. The
descriptive metrics of texts OT51 and MT51 are presented in Table 3.
The table shows significant increase in descriptive metrics, such as word count (211
(OT51) – 224 (MT51)) and syllables count respectively (506 (OT51) – 528 (MT51)).
As the number of sentences increased from 12 in OT51 to 18 in MT51, ASL and
AWL decreased. Parts of speech count within the morphological metrics is also
increased in MT51.
4.2</p>
      </sec>
      <sec id="sec-4-2">
        <title>Experiment</title>
        <p>
          To collect data and find differences in quantitative metrics of reading texts and recalls
we designed a three-stage experiment (see Fig. 4):
1. We conducted the Russian version of Wechsler Intelligence Scale test for Children
(WISC) aimed at selecting a representative sampling of respondents with average
test results. WISC comprises 27 close-ended questions and estimates participants’
general rather than topic-specific or theoretical knowledge as well as strengths and
weaknesses associated with working memory, processing speed, and long-term
memory [
          <xref ref-type="bibr" rid="ref48">48</xref>
          ]. The results of the statistical analysis of WISK aimed at selecting
respondents with similar General knowledge index are presented in Fig. 6. Of
177 native Russians, 11-year old 5th graders, we selected 64 with the average GK
of 13–17 (see Fig. 5) and streamed them into two sections: 33 subjects in Section
OT51 and 31 subjects in Section MT51.
2. Each subject read and recalled a text (either OT51 or MT51) to an individual
expert.
3. The recalls were recorded and later transcribed (see Fig. 5).
The transcribed recalls of OT51 and MT51 are comprised in the Corpus of Transcripts
with the total size of 7282 tokens (Table 4).
The Corpus of over 30 samplings of recalls of each text is viewed as representative to
conclude on the results of the experiment [
          <xref ref-type="bibr" rid="ref49">49</xref>
          ].
        </p>
        <p>Contrastive analysis of the reading texts (OT51, MT51) and participants’ recalls was
conducted based on two groups of parameters: (a) descriptive metrics and lexical
features computed with TAR and (b) propositional analysis conducted manually.</p>
        <p>Initially we computed the recalls with the help of TAR to measure the
following metrics: word count (W), syllable count (SylC), sentence count (S), average
sentence length (ASL), average word length (AWL (in syllables), FKGL (SIS), FKGL
(O), adjective count (ADJ), adverb count (ADV), pronoun count (Pron), noun count
(N), verb count (V), word frequency (Freq), Abstractness / Concreteness (A/C),
typetoken ratio (TTR) (see Table 5).</p>
        <p>On the next stage of the research we had to exclude the majority of the metrics
estimated with TAR from the analysis based on the following observations: a) length of
the recalls was fewer than 200 words, thus insufficient to measure text readability;
b) due to differences in the length of pauses, sentence length was not always correctly
estimated in transcripts either and therefore caused unreliable values of sentence
length; c) numerous repetitions of the same word in recalls while respondents were
hesitating or formulating thoughts makes computing the number of tokens in recalls
useless.</p>
        <p>V
.x Freq
eL A/C</p>
        <p>
          TTR
Stage 3. Text-level (semantic) analysis based on the assessment of text propositions.
As TAR is not yet programmed to compute semantic metrics or idea units of a text,
propositional modeling was performed manually. To assess the information scope
reproduced by respondents in recalls we applied a quantitative structural approach and
estimated the number of propositions in recalls to compare it with those in the original
text. Thus, the information in each sentence was broken into main propositions (P)
comprising the main idea and sub-propositions or arguments identifying their roles in
the events denoted by main propositions. The taxonomy of the sub-propositions
estimated includes the following: (1) Actant (Act) which comprises Agent (Ag)),
Experiencer (Exp); Object (Obj)), Source (Sour), Goal (Gl) and Instrument (Instr); (2)
Locative (Loc), Time (Temp), and Path (Pth) [
          <xref ref-type="bibr" rid="ref50 ref51">50, 51</xref>
          ]. E.g., the sentence ‘In the early 18th
century the Master erected a 22-domed festive, cheerful church’ (OT51.3) receives
the following code: ‘Time, Act (Ag) P1 (Verb) Mod1, Mod2, Mod3 (Obj).
        </p>
        <p>The obtained 65 recall files (34 for OT51, 31 for MT51) were contrasted based on
the number of propositions reproduced. Two shortest recalls (K5A14) had only
11 words forming seven total propositions. The longest recall (K5P21) was organized
in a 214-word text with 114 total propositions. An average MT51 recall consisted of
58 total propositions, whereas the average OT51 recall comprised 43 total
propositions.</p>
        <p>
          Based on the data received we estimated the average number of each type of
propositions reproduced by respondents for MT51 and OT51. To contrast difference in
recall results we visualized the normalized recall results in boxplots in Fig. 6–8
separately for the total number of propositions, main propositions and sub-propositions.
We also conducted a set of statistical tests and implemented the binomial model to
reveal differences in the total number of propositions, main propositions and
subpropositions separately for recalls of OT51 and MT51 [
          <xref ref-type="bibr" rid="ref52">52</xref>
          ]. The obtained p-values
suggest better results in recalls of text MT51 (See Table 6 and 7) manipulated with
the purpose to increase its cohesion.
Low cohesive text OT51 proves to present a higher degree of complexity for readers
and therefore and caused worse performance.
6
        </p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>Conclusion</title>
      <p>To pursue a contrastive analysis of low (OT51) and high (MT51) cohesive version of
the reading text with texts of recalls, we computed the following descriptive
quantitative metrics: sentence count, word count, average sentence length, average word
length in syllables, noun count, verb count, adjective count, adverbs count, pronouns
count, propositions count. Experiments with descriptive and lexical text
metrics measured with TAR demonstrated that they do not suffice to comprehensively
describe the quality of recalls. The metrics measured with the tool prove insufficient
to assess the quality and scope of the information in the recalls based on their small
length and numerous repetitions elevating assessment results. The feature
discriminating the scope of the information reproduced and as such the quality of recalls is
proposition count. Judged by the lower number of propositions reproduced (mean OT51 –
39,7, MT51 – 52,7), the low cohesion original text (OT51) proved to be more difficult
the for the subjects.</p>
      <p>The study confirms that cohesion is a text parameter able to improve
comprehension and as such increase the scope of the reproduced in recalls information. We also
suggest implementing propositional analysis to compare original reading texts and
recalls. The results of the current study are relevant in modern Russia to assess texts
of classroom books for cohesion and the scope of the information recalled. Based on
the analysis conducted, the research offers a guide to design a more sophisticate tool
which could discriminate propositions and semantic roles in texts. The study also
provides useful information for researchers, educators and can be of assistance for
textbook writers and test developers.</p>
    </sec>
    <sec id="sec-6">
      <title>Acknowledgement</title>
      <p>The research was financially supported by the Russian Science Foundation, grant
1818-00436.</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          1.
          <string-name>
            <surname>Solnyshkina</surname>
            ,
            <given-names>M. I.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Harkova</surname>
            ,
            <given-names>E. V.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kazachkova</surname>
            ,
            <given-names>M. B.</given-names>
          </string-name>
          :
          <article-title>The Structure of Cross-Linguistic Differences: Meaning and Context of 'Readability' and its Russian Equivalent 'Chitabelnost'</article-title>
          .
          <source>Journal of Language &amp; Education</source>
          ,
          <volume>6</volume>
          (
          <issue>1</issue>
          ),
          <fpage>103</fpage>
          -
          <lpage>119</lpage>
          (
          <year>2020</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          2.
          <string-name>
            <surname>DuBay</surname>
          </string-name>
          , W. H.:
          <article-title>The Principles of Readability</article-title>
          . Online
          <string-name>
            <surname>Submission</surname>
          </string-name>
          (
          <year>2004</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          3.
          <string-name>
            <surname>Bernhardt</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kamil</surname>
            <given-names>M.:</given-names>
          </string-name>
          <article-title>Interpreting relationships between L1 and L2 reading: Consolidating the linguistic threshold and the linguistic interdependence hypotheses</article-title>
          .
          <source>Applied Linguistics</source>
          ,
          <volume>16</volume>
          (
          <issue>1</issue>
          ),
          <fpage>15</fpage>
          -
          <lpage>34</lpage>
          (
          <year>1995</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          4.
          <string-name>
            <surname>Laufer</surname>
            ,
            <given-names>B.</given-names>
          </string-name>
          :
          <article-title>How much lexis is necessary for reading comprehension</article-title>
          ? In: H. Bejoint and P. Arnaud, editors,
          <source>Vocabulary and applied linguistics</source>
          ,
          <volume>126</volume>
          -
          <fpage>132</fpage>
          . Macmillan, Basingstoke &amp; London (
          <year>1992</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          5.
          <string-name>
            <surname>Nation</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          :
          <article-title>Learning vocabulary in another language</article-title>
          . Cambridge University Press, Cambridge (
          <year>2001</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          6.
          <string-name>
            <surname>Nation</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          :
          <article-title>How large a vocabulary is needed for reading and listening?</article-title>
          <source>The Canadian Modern Language Review</source>
          ,
          <volume>63</volume>
          (
          <issue>1</issue>
          ),
          <fpage>59</fpage>
          -
          <lpage>82</lpage>
          (
          <year>2006</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          7.
          <string-name>
            <surname>Qian</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          :
          <article-title>Assessing the roles of depth and breadth of vocabulary knowledge in reading comprehension</article-title>
          .
          <source>The Canadian Modern Language Review</source>
          ,
          <volume>56</volume>
          (
          <issue>2</issue>
          ),
          <fpage>282</fpage>
          -
          <lpage>308</lpage>
          (
          <year>1999</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          8.
          <string-name>
            <surname>Ulijn</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Strother</surname>
            ,
            <given-names>J.:</given-names>
          </string-name>
          <article-title>The effect of syntactic simplification on reading EST texts as L1 and L2</article-title>
          . Journal of Research in Reading,
          <volume>13</volume>
          (
          <issue>1</issue>
          ),
          <fpage>38</fpage>
          -
          <lpage>54</lpage>
          (
          <year>1990</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          9.
          <string-name>
            <surname>Carrell</surname>
            ,
            <given-names>P. L.</given-names>
          </string-name>
          :
          <article-title>Second language reading: Reading ability or language proficiency? Applied linguistics</article-title>
          ,
          <volume>12</volume>
          (
          <issue>2</issue>
          ),
          <fpage>159</fpage>
          -
          <lpage>179</lpage>
          (
          <year>1991</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          10.
          <string-name>
            <surname>Zareva</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          :
          <article-title>Models of lexical knowledge assessment of second language learners of English at higher levels of language proficiency</article-title>
          .
          <source>System</source>
          ,
          <volume>33</volume>
          (
          <issue>4</issue>
          ),
          <fpage>547</fpage>
          -
          <lpage>562</lpage>
          (
          <year>2005</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          11.
          <string-name>
            <surname>Uccelli</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Galloway</surname>
            ,
            <given-names>E. P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Barr</surname>
            ,
            <given-names>C. D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Meneses</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Dobbs</surname>
            ,
            <given-names>C. L.</given-names>
          </string-name>
          :
          <article-title>Beyond vocabulary: Exploring cross‐disciplinary academic‐language proficiency and its association with reading comprehension</article-title>
          . Reading Research Quarterly,
          <volume>50</volume>
          (
          <issue>3</issue>
          ),
          <fpage>337</fpage>
          -
          <lpage>356</lpage>
          (
          <year>2015</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          12.
          <string-name>
            <surname>Lyashevskaya</surname>
            ,
            <given-names>O. N.</given-names>
          </string-name>
          <string-name>
            <surname>Sharov</surname>
            ,
            <given-names>S. A.</given-names>
          </string-name>
          :
          <article-title>Chastotnyj slovar' sovremennogo russkogo yazyka (na materialah Nacional'nogo korpusa russkogo yazyka) [Frequency dictionary of modern Russian language (based on Russian national corpora)]</article-title>
          . M.,
          <string-name>
            <surname>Azbukovnik</surname>
          </string-name>
          (
          <year>2009</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          13.
          <string-name>
            <surname>Feng</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Hao</surname>
            ,
            <given-names>W.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Davies</surname>
            ,
            <given-names>M.:</given-names>
          </string-name>
          <article-title>The Graded Vocabulary of Contemporary English: 5,000 Upper-intermediate Words</article-title>
          .
          <source>Kindle Edition</source>
          ,
          <volume>579</volume>
          pages.
          <article-title>Published November 1st 2016 by Transnational Academic Exchange Service (TrAES</article-title>
          .info) (
          <year>2016</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          14.
          <string-name>
            <surname>Ryder</surname>
            ,
            <given-names>R. J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Slater</surname>
            ,
            <given-names>W. H.</given-names>
          </string-name>
          :
          <article-title>The relationship between word frequency and word knowledge</article-title>
          .
          <source>The Journal of Educational Research</source>
          ,
          <volume>81</volume>
          (
          <issue>5</issue>
          ),
          <fpage>312</fpage>
          -
          <lpage>317</lpage>
          (
          <year>1988</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref15">
        <mixed-citation>
          15.
          <string-name>
            <surname>Leroy</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kauchak</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          :
          <article-title>The effect of word familiarity on actual and perceived text difficulty</article-title>
          .
          <source>Journal of the American Medical Informatics Association</source>
          ,
          <volume>21</volume>
          (
          <issue>e1</issue>
          ),
          <fpage>1</fpage>
          -
          <lpage>4</lpage>
          (
          <year>2014</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref16">
        <mixed-citation>
          16.
          <string-name>
            <surname>Bricker</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Chapanis</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          :
          <article-title>Do incorrectly perceived stimuli convey some information? Psychological Review</article-title>
          ,
          <volume>60</volume>
          (
          <issue>3</issue>
          ),
          <fpage>181</fpage>
          -
          <lpage>188</lpage>
          (
          <year>1953</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref17">
        <mixed-citation>
          17.
          <string-name>
            <surname>Haseley</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          :
          <article-title>The relationship between cuevalue of words and their frequency of prior occurrence</article-title>
          .
          <source>Unpublished master's thesis</source>
          , Ohio university (
          <year>1957</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref18">
        <mixed-citation>
          18.
          <string-name>
            <surname>Balota</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Chumbley</surname>
          </string-name>
          , J.:
          <article-title>Are lexical decisions a good measure of lexical access? The role of word frequency in the neglected decision stage</article-title>
          .
          <source>Journal of Experimental Psychology: Human Perception &amp; Performance</source>
          ,
          <volume>10</volume>
          (
          <issue>3</issue>
          ),
          <fpage>340</fpage>
          -
          <lpage>357</lpage>
          (
          <year>1984</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref19">
        <mixed-citation>
          19.
          <string-name>
            <surname>Howes</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Solomon</surname>
          </string-name>
          , R.:
          <article-title>Visual duration threshold as a function of word-probability</article-title>
          .
          <source>Journal of Experimental Psychology</source>
          ,
          <volume>41</volume>
          (
          <issue>6</issue>
          ),
          <fpage>401</fpage>
          -
          <lpage>410</lpage>
          (
          <year>1951</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref20">
        <mixed-citation>
          20.
          <string-name>
            <surname>Jescheniak</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Levelt</surname>
            ,
            <given-names>W.</given-names>
          </string-name>
          :
          <article-title>Word ¨ frequency effects in speech production: Retrieval of syntactic information and of phonological form</article-title>
          .
          <source>Journal of Experimental Psychology: Learning</source>
          , Memory, &amp; Cognition,
          <volume>20</volume>
          (
          <issue>4</issue>
          ),
          <fpage>824</fpage>
          -
          <lpage>843</lpage>
          (
          <year>1994</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref21">
        <mixed-citation>
          21.
          <string-name>
            <surname>Monsell</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Doyle</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Haggard</surname>
            ,
            <given-names>P. N.:</given-names>
          </string-name>
          <article-title>Effects of frequency on visual word recognition tasks: Where are they</article-title>
          ?
          <source>Journal of Experimental Psychology: General</source>
          ,
          <volume>118</volume>
          (
          <issue>1</issue>
          ),
          <fpage>43</fpage>
          -
          <lpage>71</lpage>
          (
          <year>1989</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref22">
        <mixed-citation>
          22.
          <string-name>
            <surname>Rayner</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Duffy</surname>
            ,
            <given-names>S. A.</given-names>
          </string-name>
          :
          <article-title>Lexical complexity and fixation times in reading: Effects of word frequency, verb complexity, and lexical ambiguity</article-title>
          .
          <source>Memory &amp; Cognition</source>
          ,
          <volume>14</volume>
          (
          <issue>3</issue>
          ),
          <fpage>191</fpage>
          -
          <lpage>201</lpage>
          (
          <year>1986</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref23">
        <mixed-citation>
          23.
          <string-name>
            <surname>Klare</surname>
            ,
            <given-names>G. R.</given-names>
          </string-name>
          :
          <article-title>The role of word frequency in readability</article-title>
          .
          <source>Elementary English</source>
          ,
          <volume>45</volume>
          (
          <issue>1</issue>
          ),
          <fpage>12</fpage>
          -
          <lpage>22</lpage>
          (
          <year>1968</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref24">
        <mixed-citation>
          24.
          <string-name>
            <surname>Lyashevskaya</surname>
            ,
            <given-names>O. N.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sharov</surname>
            ,
            <given-names>S. A.</given-names>
          </string-name>
          :
          <article-title>Chastotnyj slovar' nacional'nogo korpusa russkogo yazyka: koncepciya i tekhnologiya sozdaniya. [Frequency dictionary of Russian national corpora: concept and</article-title>
          technology of compiling)], http://www.dialog21.ru/digests/dialog2008/materials/html/53. htm,
          <source>last accessed</source>
          <year>2020</year>
          /10/30.
        </mixed-citation>
      </ref>
      <ref id="ref25">
        <mixed-citation>
          25.
          <article-title>Word frequency data</article-title>
          , https://www.wordfrequency.info/,
          <source>last accessed</source>
          <year>2020</year>
          /10/29.
        </mixed-citation>
      </ref>
      <ref id="ref26">
        <mixed-citation>
          26.
          <string-name>
            <surname>Templin</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          :
          <article-title>Certain language skills in children: Their development and interrelationships</article-title>
          . Minneapolis: The University of Minnesota Press (
          <year>1957</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref27">
        <mixed-citation>
          27.
          <string-name>
            <surname>Baker</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          :
          <article-title>Using corpora in discourse analysis</article-title>
          . A&amp;
          <string-name>
            <surname>C Black</surname>
          </string-name>
          (
          <year>2006</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref28">
        <mixed-citation>
          28.
          <string-name>
            <surname>Shermis</surname>
            ,
            <given-names>M. D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Burstein</surname>
          </string-name>
          , J.:
          <article-title>Handbook of automated essay evaluation: Current applications and new directions</article-title>
          .
          <source>Routledge</source>
          (
          <year>2013</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref29">
        <mixed-citation>
          29.
          <string-name>
            <surname>Maybury</surname>
            ,
            <given-names>M.:</given-names>
          </string-name>
          <article-title>Advances in automatic text summarization</article-title>
          . MIT press (
          <year>1999</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref30">
        <mixed-citation>
          30.
          <string-name>
            <surname>Pratt</surname>
            ,
            <given-names>M. W.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Luszcz</surname>
            ,
            <given-names>M. A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>MacKenzie-Keating</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Manning</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          :
          <article-title>Thinking about stories: The story schema in metacognition</article-title>
          .
          <source>Journal of Verbal Learning &amp; Verbal Behavior</source>
          ,
          <volume>21</volume>
          ,
          <fpage>493</fpage>
          -
          <lpage>505</lpage>
          (
          <year>1982</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref31">
        <mixed-citation>
          31.
          <string-name>
            <surname>Shaughnessy</surname>
            ,
            <given-names>J. J.</given-names>
          </string-name>
          :
          <article-title>Confidence-judgment accuracy as a predictor of test performance</article-title>
          .
          <source>Journal of Research in Personality</source>
          ,
          <volume>13</volume>
          ,
          <fpage>505</fpage>
          -
          <lpage>514</lpage>
          (
          <year>1979</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref32">
        <mixed-citation>
          32.
          <string-name>
            <surname>Wearn</surname>
            ,
            <given-names>Y.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Askwall</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          :
          <article-title>On some sources of metacomprehension</article-title>
          .
          <source>Scandinavian Journal of Psychology</source>
          ,
          <volume>22</volume>
          ,
          <fpage>17</fpage>
          -
          <lpage>25</lpage>
          (
          <year>1981</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref33">
        <mixed-citation>
          33.
          <string-name>
            <surname>Lefèvre</surname>
            ,
            <given-names>N.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Lories</surname>
          </string-name>
          , G.:
          <article-title>Text cohesion and metacomprehension: Immediate and delayed judgments</article-title>
          .
          <source>Memory &amp; cognition</source>
          ,
          <volume>32</volume>
          (
          <issue>8</issue>
          ),
          <fpage>1238</fpage>
          -
          <lpage>1254</lpage>
          (
          <year>2004</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref34">
        <mixed-citation>
          34.
          <string-name>
            <surname>McNamara</surname>
            ,
            <given-names>D. S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kintsch</surname>
            ,
            <given-names>W.</given-names>
          </string-name>
          :
          <article-title>Learning from text: Effects of prior knowledge and text coherence</article-title>
          .
          <source>Discourse Processes</source>
          ,
          <volume>22</volume>
          ,
          <fpage>247</fpage>
          -
          <lpage>287</lpage>
          (
          <year>1996</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref35">
        <mixed-citation>
          35.
          <string-name>
            <surname>Ozuru</surname>
            ,
            <given-names>Y.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Briner</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Best</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>McNamara</surname>
            ,
            <given-names>D. S.:</given-names>
          </string-name>
          <article-title>Contributions of self-explanation to comprehension of high-and low-cohesion texts</article-title>
          .
          <source>Discourse Processes</source>
          ,
          <volume>47</volume>
          (
          <issue>8</issue>
          ),
          <fpage>641</fpage>
          -
          <lpage>667</lpage>
          (
          <year>2010</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref36">
        <mixed-citation>
          36.
          <string-name>
            <surname>Ozuru</surname>
            ,
            <given-names>Y.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Dempsey</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>McNamara</surname>
            ,
            <given-names>D. S.:</given-names>
          </string-name>
          <article-title>Prior knowledge, reading skill, and text cohesion in the comprehension of science texts</article-title>
          .
          <source>Learning and instruction</source>
          ,
          <volume>19</volume>
          (
          <issue>3</issue>
          ),
          <fpage>228</fpage>
          -
          <lpage>242</lpage>
          (
          <year>2009</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref37">
        <mixed-citation>
          37.
          <string-name>
            <surname>Cain</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Nash</surname>
            ,
            <given-names>H. M.:</given-names>
          </string-name>
          <article-title>The influence of connectives on young readers' processing and comprehension of text</article-title>
          .
          <source>Journal of Educational Psychology</source>
          ,
          <volume>103</volume>
          (
          <issue>2</issue>
          ), 429 p. (
          <year>2011</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref38">
        <mixed-citation>
          38.
          <string-name>
            <surname>Solnyshkina</surname>
            ,
            <given-names>M. I.</given-names>
          </string-name>
          , Solov'ev, V. D.,
          <string-name>
            <surname>Andreeva</surname>
            ,
            <given-names>M. I.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Danilov</surname>
            ,
            <given-names>A. V.</given-names>
          </string-name>
          :
          <article-title>Vliyanie svyaznosti teksta na ego vospriyatie: eksperimental'nyj podhod</article-title>
          .
          <source>In: I.A. Boduen de Kurtene i mirovaya lingvistika [Influence of text cohesion on its comprehension: experimental approach]</source>
          ,
          <volume>212</volume>
          -
          <fpage>216</fpage>
          (
          <year>2019</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref39">
        <mixed-citation>
          39.
          <string-name>
            <surname>Bouquet</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Warglien</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          :
          <article-title>Mental models and local models semantics: the problem of information integration</article-title>
          .
          <source>In: Proceedings of the European Conference on Cognitive Science</source>
          ,
          <volume>169</volume>
          -
          <fpage>178</fpage>
          . University of Siena Italy (
          <year>1999</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref40">
        <mixed-citation>
          40.
          <string-name>
            <surname>Walsh</surname>
            ,
            <given-names>C. R.</given-names>
          </string-name>
          , Johnson-Laird,
          <string-name>
            <surname>P. N.:</surname>
          </string-name>
          <article-title>Co-reference and reasoning</article-title>
          .
          <source>Memory &amp; Cognition</source>
          ,
          <volume>32</volume>
          (
          <issue>1</issue>
          ),
          <fpage>96</fpage>
          -
          <lpage>106</lpage>
          (
          <year>2004</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref41">
        <mixed-citation>
          41.
          <string-name>
            <surname>Fillmore</surname>
            ,
            <given-names>C. J.:</given-names>
          </string-name>
          <article-title>Frame semantics and the nature of language</article-title>
          .
          <source>In: Annals of the New York Academy of Sciences: Conference on the Origin and Development of Language and Speech</source>
          ,
          <volume>280</volume>
          ,
          <fpage>20</fpage>
          -
          <lpage>32</lpage>
          . New York Academy of Sciences, New York (
          <year>1976</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref42">
        <mixed-citation>
          42.
          <string-name>
            <surname>Fillmore</surname>
            ,
            <given-names>Charles J.:</given-names>
          </string-name>
          <article-title>Some problems for case grammar</article-title>
          .
          <source>In: R. J. O'Brien, editor, 22nd Annual Round Table. Linguistics: Developments of the Sixties - Viewpoints of the Seventies. Volume 24 of Monograph Series on Language and Linguistics</source>
          ,
          <volume>35</volume>
          -
          <fpage>56</fpage>
          . Georgetown University Press, Washington,
          <string-name>
            <surname>D.C.</surname>
          </string-name>
          (
          <year>1971</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref43">
        <mixed-citation>
          43.
          <article-title>TAR text analyser</article-title>
          , http://tykau.pythonanywhere.com/,
          <source>last accessed</source>
          <year>2020</year>
          /10/30.
        </mixed-citation>
      </ref>
      <ref id="ref44">
        <mixed-citation>
          44.
          <string-name>
            <surname>Oborneva</surname>
            ,
            <given-names>I.V.</given-names>
          </string-name>
          :
          <article-title>Avtomatizirovannaya otsenka slozhnosti uchebnykh tekstov na osnove statisticheskikh parametrov [Automated estimation of complexity of educational texts on the basis of statistical parameters]</article-title>
          .
          <source>Pedagogy Cand. Diss</source>
          . Moscow (
          <year>2006</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref45">
        <mixed-citation>
          45.
          <string-name>
            <surname>Solovyev</surname>
            ,
            <given-names>V.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Ivanov</surname>
            ,
            <given-names>V.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Solnyshkina</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          :
          <article-title>Assessment of reading difficulty levels in Russian academic texts: Approaches and metrics</article-title>
          .
          <source>Journal of intelligent &amp; fuzzy systems</source>
          ,
          <volume>34</volume>
          (
          <issue>5</issue>
          ),
          <fpage>3049</fpage>
          -
          <lpage>3058</lpage>
          (
          <year>2018</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref46">
        <mixed-citation>
          46. MyStem, https://yandex.ru/dev/mystem/,
          <source>last accessed</source>
          <year>2020</year>
          /10/30.
        </mixed-citation>
      </ref>
      <ref id="ref47">
        <mixed-citation>
          47.
          <string-name>
            <surname>Wechsler</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          :
          <article-title>Wechsler intelligence scale for children-fifth edition</article-title>
          . Bloomington, MN: Pearson (
          <year>2014</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref48">
        <mixed-citation>
          48.
          <string-name>
            <surname>Filimonenko</surname>
            ,
            <given-names>Y. I.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Timofeev</surname>
            ,
            <given-names>V. I.</given-names>
          </string-name>
          :
          <article-title>Rukovodstvo k metodike issledovaniya intellekta u detei D. Vekslera (WISC) (</article-title>
          <year>1994</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref49">
        <mixed-citation>
          49.
          <string-name>
            <surname>Biber</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          :
          <article-title>Representativeness in corpus design</article-title>
          .
          <source>Literary and linguistic computing</source>
          ,
          <volume>8</volume>
          (
          <issue>4</issue>
          ),
          <fpage>243</fpage>
          -
          <lpage>257</lpage>
          (
          <year>1993</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref50">
        <mixed-citation>
          50.
          <string-name>
            <surname>Starodumova</surname>
            ,
            <given-names>E. A.</given-names>
          </string-name>
          :
          <article-title>Sintaksis sovremennogo russkogo yazyka [Russian syntax]</article-title>
          . Vladivistok: Far East University Publishing (
          <year>2005</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref51">
        <mixed-citation>
          51.
          <string-name>
            <surname>Tesnière</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          : Éléments de syntaxe structural (
          <year>1959</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref52">
        <mixed-citation>
          52.
          <string-name>
            <surname>Lehmann</surname>
            ,
            <given-names>E. L.</given-names>
          </string-name>
          :
          <article-title>Testing Statistical Hypotheses</article-title>
          . Wiley, 600 p. (
          <year>1986</year>
          ).
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>