<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Archiving and Interchange DTD v1.0 20120330//EN" "JATS-archivearticle1.dtd">
<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Spoken Conversational Agents for Older Adults: Who Are the Stakeholders and What Do They Expect?</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Jelte van Waterschoot</string-name>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Iris Hendrickx</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Arif Khan</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Catia Cucchiarini</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Helmer Strik</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Louis ten Bosch</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Rob Tieben</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Centre for Language Studies, Centre for Language and Speech Technology, Radboud University</institution>
          ,
          <addr-line>Erasmusplein 1, 6500 HD, Nijmegen</addr-line>
          ,
          <country country="NL">The Netherlands</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Games Solutions Lab</institution>
          ,
          <addr-line>Vonderweg 1, 5611 BK, Eindhoven</addr-line>
          ,
          <country country="NL">The Netherlands</country>
        </aff>
        <aff id="aff2">
          <label>2</label>
          <institution>Human Media Interaction, University of Twente</institution>
          ,
          <addr-line>Drienerlolaan 5, 7522 NB, Enschede</addr-line>
          ,
          <country country="NL">The Netherlands</country>
        </aff>
      </contrib-group>
      <abstract>
        <p>In this paper we discuss our road map to design a Dutch spoken conversational agent that helps older adults with self-management of their well-being. We conducted three usability studies with our conversational agent, each time after discussing it with diferent stakeholders. We discuss the challenges incorporating each stakeholder's wishes and needs whilst iteratively designing our agent.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;conversational agents</kwd>
        <kwd>dialogue design</kwd>
        <kwd>stakeholders</kwd>
        <kwd>health</kwd>
        <kwd>self-management</kwd>
        <kwd>older adults</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <sec id="sec-1-1">
        <title>In our own research we have been develop</title>
        <p>
          ing a conversational agent (CA) that should
Self-management has become an important support older adults in self-management of
feature in (western) communities, where we their well-being [
          <xref ref-type="bibr" rid="ref4">4</xref>
          ]. Self-management is a
colstrive to live independently for as long as we laborative efort between older adults and a
can. This is a challenge for older adults who CA, to promote activation and empowerment
might face physical limitations, such as re- and adopt health-promoting behaviours [
          <xref ref-type="bibr" rid="ref5 ref6">5, 6</xref>
          ].
duced mobility, hearing problems and visual We have explicitly chosen for spoken
interacimpairment, or limited support from a social tion because this is a low-threshold form of
network. A social robot might support them communication for this target group. Digital
with self-management [
          <xref ref-type="bibr" rid="ref1">1</xref>
          ], e.g. with physical literacy is generally low in older adults, so
usactivities [
          <xref ref-type="bibr" rid="ref2">2</xref>
          ] or social skills [
          <xref ref-type="bibr" rid="ref3">3</xref>
          ]. ing a chatbot can be a hurdle, while a spoken
interface would definitely be more accessible,
except for people with speaking or hearing
problems. Speaking to a device is certainly
easier than typing, which can be problematic,
e.g. due to arthritis or visual impairments [
          <xref ref-type="bibr" rid="ref7">7</xref>
          ].
        </p>
        <p>
          A systematic literature review on
conversational agents in the health domain showed
that interaction with older adults is seen as
one of the big challenges in agent
development [
          <xref ref-type="bibr" rid="ref8">8</xref>
          ]. Diferent stakeholders are involved
in designing such a CA: care professionals,
end-users (older adults), CA developers, fund- as researchers are interested how
conversaing agencies and researchers. In this paper tions from a positive psychology point of view
we discuss the challenges that we faced in our would benefit end-users [ 16]. We created a
own research and the lessons we learned, in small scripted dialogue that would ask about
the hope that these might be useful to others activities and social relationships, two
imporconducting similar research. tant factors in a persons well-being about
their daily activities and quality of life [17].
        </p>
        <p>
          The conversation took about 2 minutes in
2. Speech-based CAs for total per participant. There was some
limwell-being ited Natural Language Understanding (NLU)
capability in the Behaviour-based
LanguageWe are not the first to use a spoken CA for sup- Interactive Speaking Systems (BLISS)
protoporting self-management of older adults [
          <xref ref-type="bibr" rid="ref9">9</xref>
          ]. type for interpreting user answers. For
exA CA can be deployed to reduce loneliness or ample, if the user answered a question with
provide assistance in daily life [
          <xref ref-type="bibr" rid="ref10">10, 11, 12</xref>
          ]. For “I think that would be cycling.”, the system
example, [
          <xref ref-type="bibr" rid="ref3">3</xref>
          ] developed a virtual CA that en- would ask “What would you miss most if you
gaged with older adults on a regular basis over wouldn’t cycle?”.
a longer period of time to help them improve At the early stage of our research we
extheir social skills. A study by [13] looked at a plored how adults with limited experience
virtual companion agent for older adults. The with agents interact with our CA. We went
authors found that topics that are generally in- to three public Dutch conferences related to
teresting include storytelling, the weather, the language and health using a demo stand to
family, and future plans they have with a live- evaluate the prototype and dialogue with 56
in companion. Many practical issues remain people. These conferences were in a noisy
enwith speech-based systems, and specifically vironment, in spaces with many people and
for older adults, speech recognition accuracy provided an ecologically valid test to see if
can be improved by pre-processing the au- our system was robust enough in natural
condio [14]. Current voice interfaces are trained ditions.
for younger audiences, and even with
preprocessing, syllable segmentation for older 3.2. Online data collection
adults remains an issue [15].
        </p>
      </sec>
      <sec id="sec-1-2">
        <title>Due to the COVID-19 crisis we had to switch</title>
        <p>
          focus from physical interactions to online
in3. Dialogue Design teractions. Therefore we designed a dialogue
oriented towards older adults about social
reWe conducted a field and an online usability lationships and activities and how the
COVIDstudy and co-designed a dialogue with health- 19 crisis impacted them. The dialogue design
care professionals from the field. contained questions about social relationships
and activities and how the COVID-19 crisis
3.1. Field data collection has impacted this. Then, we contacted 6 older
adults (70+) through a telephone call and
evalTowards the end of 2019, we conducted field uated the questions in a human-human
teleusability studies with the first version of our phone conversation. After correcting the
diDutch spoken dialogue system BLISS [
          <xref ref-type="bibr" rid="ref4">4</xref>
          ]. We alogues for unclear, unnecessary and
inappropriate questions, we implemented these
questions in the BLISS CA. We contacted 10
participants, of whom 7 are older adults, to
talk to the CA. Unfortunately, we could not
visit the participants and thus set up the CA
remotely by running it locally on a computer
and set up a video call via Zoom, MSTeams or
Skype with the participants, who were using
either a tablet or a laptop. Most participants
were assisted by a younger family member or
were already familiar with video calls. Each
conversation took about 10 minutes, and an
excerpt of asking about social relationships
(family) from one conversation is shown in
Table 1. Note that in this conversation the
question of the agent on line 11 does not make
much sense given the previous response of
the user.
#
1
        </p>
      </sec>
      <sec id="sec-1-3">
        <title>After these two data collections, we invited</title>
        <p>two domain experts, healthcare workers, to
evaluate and improve our dialogue designs
and co-design a better dialogue that is more
suited for older adults in a healthcare facility.
Based on the feedback, we improved the
dialogues to include more self-disclosure and
backchanneling by the system. An example of
this is shown in Table 2. We tested these
dialogues with 7 healthy adults, of whom 4 were
over the age of 70, and the others between 50
and 70 years old.</p>
      </sec>
    </sec>
    <sec id="sec-2">
      <title>4. Stakeholders</title>
      <sec id="sec-2-1">
        <title>Designing and testing a spoken CA requires</title>
        <p>the help by and collaboration with many
different stakeholders. Each stakeholder has
different wishes and needs they bring to the
table. The first and foremost stakeholders
are the older adults, the end-users of our CA.</p>
        <p>They need to be comfortable with the technol- more possibilities for other stakeholders to
ogy and this needs to be accessible to them. It ask for support because of new discoveries in
can take up to two months before people ac- research could benefit all stakeholders.
cept social robots, and even take half a year be- Finally, we as researchers want to
evalufore a CA will be integrated in its environment ate the use of the CA, the user experience,
[18]. [12] mention the following things that the conversation flow, long-term usage and
are important to the older adults: retaining test novel ideas to publish and develop
knowlcontrol, being encouraged for tasks or activ- edge. We design prototypes based on theories
ities, safeguard their privacy and usefulness and/or datasets and evaluate them with
endand quality of social skills of an agent. In our users. Only recently more focus has shifted to
online study, older adults also commented on co-designing with end-users, actively
involvthe voice lacking clarity and empathy, which ing them in the whole design process of CAs.
is also found in earlier research [19, 20]. Researchers might still have problems
explain</p>
        <p>The second type of stakeholders are the ing to other stakeholders what is possible and
healthcare professionals. Their main interest what is not, and to fully accommodate other
is providing the best care they can in which stakeholders’ needs, especially the end-users.
the CA must be a support tool and not a hassle. All these stakeholders’ expectations impact
In the co-design session, the healthcare work- the design of the CA and we have to combine
ers who were in direct contact with clients the wishes and needs of all parties. In fact, we
expressed the need for a CA that would (just) experienced that this can be very challenging
engage, entertain and distract clients; they during our data collections.
preferred an intervention that can help with
boredom and loneliness. They did not yet see
the usefulness or applicability of a personal 5. Conclusion
user profile that could be collected through
such an engaging CA, in contrast to what The application of interactive and intelligent
some of healthcare management would like CAs ofers many possibilities to the
healthto see. care field. We believe that a personalised CA</p>
        <p>Thirdly, there are CA developers who im- can help both clients and professionals:
implement state-of-the-art technologies in the proved self-management for clients, and a
betCA. Their interest is in seeing how their tech- ter insight into clients’ needs and wishes for
nology is accepted by the end-users and it- professionals. Discussions with healthcare
eratively improve the technology. However, management have confirmed this.
much (research) software becomes outdated The healthcare workers, the professionals
due to shifts in maintenance and time and/or who are in contact with the clients on a daily
funding is too limited for achieving the re- base, are the gatekeepers of these
intervensearch goals. tions. Their main focus is on providing good</p>
        <p>Fourthly, funding agencies often require a care for the client, and especially during the
clear valorisation and societal and scientific COVID-19 pandemic their time is pressed. As
impact of the research, focusing on novel re- such, they are naturally looking for solutions
search. They often only see the global part of a that provide an immediate improvement.
project and have to deal with many projects at There is an inverted mismatch between the
the same time. They are usually only involved current needs and wishes of healthcare
produring writing of proposals and reviewing of fessionals and end-users, and the design and
the project mid-way and at the end. Adding technological possibilities of our CA for
researchers and CA developers. Professionals in
direct contact with older adults are satisfied
with a system that (just) engages and gives
attention, while healthcare management is also
interested in the longer-term benefits of
collecting valuable data about clients, in order to
provide even better personal care.
Additionally, CA developers are the most
knowledgeable about the CA’s capabilities and are
interested in usability of their latest technology.</p>
        <p>Mindset broadening seems to be required.</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>Acknowledgments</title>
      <sec id="sec-3-1">
        <title>This work is part of the research</title>
        <p>programme Data2-Person with
project no. 628.011.029, which
is (partially) financed by the
Dutch Research Council (NWO).</p>
        <p>We thank the reviewers for their
valuable suggestions.
Social support agents for older adults: health: a mixed methods study, BMJ
longitudinal afective computing in the Open 6 (2016) e010091. doi:10.1136/
home, Journal on Multimodal User In- bmjopen-2015-010091.</p>
        <p>terfaces 9 (2015) 79–88. [18] M. M. A. de Graaf, S. B. Allouch, J. A.
[11] B. Spillane, E. Gilmartin, C. Saam, B. R. G. M. van Dijk, Why Would I Use This in
Cowan, V. Wade, Adele: Care and com- My Home? A Model of Domestic Social
panionship for independent aging., in: Robot Acceptance, Human–Computer
ICAHGCA@ AAMAS, 2018, pp. 18–24. Interaction 34 (2019) 115–173. doi:10.
[12] C. Tsiourti, E. Joly, C. Wings, M. B. 1080/07370024.2017.1312406,
Moussa, K. Wac, Virtual assistive com- publisher: Taylor &amp; Francis.
panions for older adults: qualitative field [19] J. Oliveira, G. S. Martins, A. Jegundo,
study and design implications, in: Pro- C. Dantas, C. Wings, L. Santos, J. Dias,
ceedings of the 8th International Confer- F. Perdigão, Speaking robots: The
chalence on Pervasive Computing Technolo- lenges of acceptance by the ageing
sogies for Healthcare, ICST (Institute for ciety, in: 2017 26th IEEE International
Computer Sciences, Social-Informatics Symposium on Robot and Human
Interand . . . , 2014, pp. 57–64. active Communication (RO-MAN), 2017,
[13] L. P. Vardoulakis, L. Ring, B. Barry, C. L. pp. 1285–1290. doi:10.1109/ROMAN.</p>
        <p>Sidner, T. Bickmore, Designing rela- 2017.8172470, iSSN: 1944-9437.
tional agents as long term social com- [20] J. James, C. I. Watson, B.
MacDonpanions for older adults, in: Interna- ald, Artificial Empathy in Social
tional Conference on Intelligent Virtual Robots: An analysis of Emotions in
Agents, Springer, 2012, pp. 289–302. Speech, in: 2018 27th IEEE
Interna[14] S. Kwon, S.-J. Kim, J. Y. Choeh, Prepro- tional Symposium on Robot and Human
cessing for elderly speech recognition of Interactive Communication (RO-MAN),
smart devices, Computer Speech &amp; Lan- 2018, pp. 632–637. doi:10.1109/ROMAN.
guage 36 (2016) 110–121. doi:10.1016/ 2018.8525652, iSSN: 1944-9437.
j.csl.2015.09.002.
[15] G. Son, S. Kwon, Y. Lim, Speech rate
control for improving elderly speech
recognition of smart devices, Advances in
Electrical and Computer Engineering 17
(2017) 79–85. Publisher: Stefan cel Mare</p>
        <p>University of Suceava.
[16] M. E. P. Seligman, Positive
psychology, positive prevention, and positive
therapy, in: Handbook of positive
psychology, Oxford University Press,
NY, US, 2002, pp. 3–9. doi:10.1017/</p>
        <p>CBO9781107415324.004.
[17] M. Huber, M. v. Vliet, M.
Giezenberg, B. Winkens, Y. Heerkens, P. C.</p>
        <p>Dagnelie, J. A. Knottnerus,
Towards a ‘patient-centred’
operationalisation of the new dynamic concept of</p>
      </sec>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          [1]
          <string-name>
            <given-names>M.</given-names>
            <surname>Rijken</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Jones</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Heijmans</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Dixon</surname>
          </string-name>
          ,
          <article-title>Supporting self-management, in: Caring for People with Chronic Conditions: A Health System Perspective</article-title>
          , 1st ed.,
          <string-name>
            <surname>McGraw-Hill Education</surname>
          </string-name>
          (UK),
          <year>2008</year>
          , pp.
          <fpage>116</fpage>
          -
          <lpage>142</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          [2]
          <string-name>
            <given-names>R.</given-names>
            <surname>Kocielnik</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Xiao</surname>
          </string-name>
          ,
          <string-name>
            <given-names>D.</given-names>
            <surname>Avrahami</surname>
          </string-name>
          , G. Hsieh,
          <article-title>Reflection companion: A conversational system for engaging users in reflection on physical activity</article-title>
          ,
          <source>Proc. ACM Interact. Mob. Wearable Ubiquitous Technol</source>
          .
          <volume>2</volume>
          (
          <year>2018</year>
          ). doi:
          <volume>10</volume>
          .1145/ 3214273.
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          [3]
          <string-name>
            <given-names>R.</given-names>
            <surname>Ali</surname>
          </string-name>
          , E. Hoque,
          <string-name>
            <given-names>P.</given-names>
            <surname>Duberstein</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Schubert</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S. Z.</given-names>
            <surname>Razavi</surname>
          </string-name>
          ,
          <string-name>
            <given-names>B.</given-names>
            <surname>Kane</surname>
          </string-name>
          ,
          <string-name>
            <given-names>C.</given-names>
            <surname>Silva</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J. S.</given-names>
            <surname>Daks</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Huang</surname>
          </string-name>
          ,
          <string-name>
            <surname>K. Van Orden</surname>
          </string-name>
          ,
          <article-title>Aging and engaging: A pilot randomized controlled trial of an online conversational skills coach for older adults</article-title>
          ,
          <source>The American Journal of Geriatric Psychiatry</source>
          (
          <year>2020</year>
          ). doi:
          <volume>10</volume>
          .1016/j.jagp.
          <year>2020</year>
          .
          <volume>11</volume>
          .004.
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          [4]
          <string-name>
            <surname>J. van Waterschoot</surname>
          </string-name>
          ,
          <string-name>
            <surname>I. Hendrickx</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Khan</surname>
          </string-name>
          , E. Klabbers, M. de Korte,
          <string-name>
            <given-names>H.</given-names>
            <surname>Strik</surname>
          </string-name>
          ,
          <string-name>
            <given-names>C.</given-names>
            <surname>Cucchiarini</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Theune</surname>
          </string-name>
          ,
          <string-name>
            <surname>BLISS:</surname>
          </string-name>
          <article-title>An agent for collecting spoken dialogue data about health and wellbeing</article-title>
          ,
          <source>in: Proceedings of the 12th Language Resources and Evaluation Conference</source>
          , European Language Resources Association, Marseille, France,
          <year>2020</year>
          , pp.
          <fpage>449</fpage>
          -
          <lpage>458</lpage>
          . URL: https://www. aclweb.org/anthology/2020.lrec-
          <volume>1</volume>
          .
          <fpage>57</fpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          [5]
          <string-name>
            <given-names>M. S.</given-names>
            <surname>Goldstein</surname>
          </string-name>
          ,
          <article-title>The persistence and resurgence of medical pluralism</article-title>
          ,
          <source>Journal of Health Politics, Policy and Law</source>
          <volume>29</volume>
          (
          <year>2004</year>
          )
          <fpage>925</fpage>
          -
          <lpage>946</lpage>
          . doi:
          <volume>10</volume>
          .1215/
          <fpage>03616878</fpage>
          -29-4-5-925.
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          [6]
          <string-name>
            <given-names>K.</given-names>
            <surname>Farrell</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M. N.</given-names>
            <surname>Wicks</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J. C.</given-names>
            <surname>Martin</surname>
          </string-name>
          ,
          <article-title>Chronic disease self-management improved with enhanced self-eficacy</article-title>
          ,
          <source>Clinical Nursing Research</source>
          <volume>13</volume>
          (
          <year>2004</year>
          )
          <fpage>289</fpage>
          -
          <lpage>308</lpage>
          . doi:
          <volume>10</volume>
          .1177/1054773804267878, publisher: SAGE Publications Inc.
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          [7]
          <string-name>
            <given-names>S. J.</given-names>
            <surname>Czaja</surname>
          </string-name>
          ,
          <string-name>
            <given-names>N.</given-names>
            <surname>Charness</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A. D.</given-names>
            <surname>Fisk</surname>
          </string-name>
          ,
          <string-name>
            <given-names>C.</given-names>
            <surname>Hertzog</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S. N.</given-names>
            <surname>Nair</surname>
          </string-name>
          ,
          <string-name>
            <given-names>W. A.</given-names>
            <surname>Rogers</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J.</given-names>
            <surname>Sharit</surname>
          </string-name>
          ,
          <article-title>Factors predicting the use of technology: Findings from the center for research and education on aging and technology enhancement (create)</article-title>
          ., Psychology and aging
          <volume>21</volume>
          (
          <year>2006</year>
          )
          <fpage>333</fpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          [8]
          <string-name>
            <given-names>J. L. Z.</given-names>
            <surname>Montenegro</surname>
          </string-name>
          ,
          <string-name>
            <surname>C. A. da Costa</surname>
          </string-name>
          , R. da Rosa Righi,
          <article-title>Survey of conversational agents in health</article-title>
          ,
          <source>Expert Systems with Applications</source>
          <volume>129</volume>
          (
          <year>2019</year>
          )
          <fpage>56</fpage>
          -
          <lpage>67</lpage>
          . doi:
          <volume>10</volume>
          . 1016/j.eswa.
          <year>2019</year>
          .
          <volume>03</volume>
          .054.
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          [9]
          <string-name>
            <given-names>R.</given-names>
            <surname>Jaber</surname>
          </string-name>
          ,
          <string-name>
            <given-names>D.</given-names>
            <surname>McMillan</surname>
          </string-name>
          ,
          <article-title>Conversational user interfaces on mobile devices: Survey</article-title>
          , in
          <source>: Proceedings of the 2nd Conference on Conversational User Interfaces</source>
          ,
          <source>CUI '20</source>
          ,
          <string-name>
            <surname>Association</surname>
          </string-name>
          for Computing Machinery,
          <year>2020</year>
          , pp.
          <fpage>1</fpage>
          -
          <lpage>11</lpage>
          . doi:
          <volume>10</volume>
          .1145/ 3405755.3406130.
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          [10]
          <string-name>
            <given-names>L.</given-names>
            <surname>Ring</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Shi</surname>
          </string-name>
          ,
          <string-name>
            <given-names>K.</given-names>
            <surname>Totzke</surname>
          </string-name>
          , T. Bickmore,
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>