Holds alternative versions of a single citation, for example, the same citation in multiple languages or a single citation tagged as both a <mixed-citation> complete with punctuation and spacing preserved and as an <element-citation> with punctuation and spacing removed.
<!ELEMENT citation-alternatives
%citation-alternatives-model; >(element-citation | mixed-citation)+
A single citation in two languages/scripts:
...
<ref id="B30">
<citation-alternatives>
<mixed-citation publication-type="journal" publication-format="print" xml:lang="ja">
<person-group person-group-type="author">
<string-name name-style="eastern">
<surname>柿崎</surname>
<given-names>一郎</given-names>
</string-name></person-group>. <year iso-8601-date="2000">2000</year>.
『<source>タイ経済と鉄道1835 年～1935 年</source>』
<publisher-name>日本経済評論社</publisher-name>
</mixed-citation>
<mixed-citation publication-type="journal" publication-format="print" xml:lang="en">
<person-group person-group-type="author">
<string-name name-style="western">
<surname>Kakizaki</surname>, <given-names>Ichiro</given-names>
</string-name></person-group>. <year iso-8601-date="2000">2000</year>.
<source>Thai Economy and Railway 1885-1935</source>.
<publisher-loc>Tokyo</publisher-loc>: <publisher-name>Nihon Keizai
Hyoronsha</publisher-name> (in Japanese)</mixed-citation>
</citation-alternatives>
</ref>
...
A single citation tagged as both an element citation and as a mixed citation:
...
<ref id="B8">
<label>8</label>
<citation-alternatives>
<element-citation publication-type="journal">
<person-group person-group-type="author">
<name><surname>Weissert</surname>
<given-names>W</given-names></name>
<name><surname>Wan</surname>
<given-names>T</given-names></name>
<name><surname>Livieratos</surname>
<given-names>B</given-names></name>
<name><surname>Katz</surname>
<given-names>S</given-names></name>
</person-group>
<article-title>Effects and costs of day-care
services for the chronically ill: a randomized
experiment</article-title>
<source>Medical Care</source>
<year iso-8601-date="1980">1980</year>
<volume>18</volume>
<fpage>567</fpage>
<lpage>584</lpage>
<pub-id pub-id-type="pmid">6772889</pub-id>
</element-citation>
<mixed-citation publication-type="journal">
<string-name><surname>Weissert</surname>,
<given-names>W</given-names></string-name>,
<string-name><surname>Wan</surname>,
<given-names>T</given-names></string-name>,
<string-name><surname>Livieratos</surname>,
<given-names>B</given-names></string-name>,
<string-name><surname>Katz</surname>,
<given-names>S</given-names></string-name>.
<article-title>Effects and costs of day-care
services for the chronically ill: a randomized
experiment</article-title>. <source>Medical Care</source>
<year iso-8601-date="1980">1980</year>; <volume>18</volume>:
<fpage>567</fpage>–<lpage>584</lpage>.
[<pub-id pub-id-type="pmid">6772889</pub-id>].
</mixed-citation>
</citation-alternatives>
</ref>
...