underlinesee <underline-end>see <underline-start>see @underline-style
Underline Attributes parameter entitysee %underline-atts;
<underline-start> Underline Start
undisclosed authorsee <anonymous>
Uniform Resource Identifieruse <uri>
Uniform Resource Identifier (URI)
unique identifiersee @id
units of measuresee <size>use @units
universitysee <aff>see <institution>
university degreeuse <degrees>
unknown, authorsee <anonymous>
unordered listsee <list>
unprinted-itemsee <supplementary-material>
unstructured citation textsee <comment>
Unstructured Keyword Group Attributes parameter entitysee %unstructured-kwd-group-atts;
Unstructured Keyword Group Class
Unstructured Keyword Group Elements parameter entitysee %unstructured-kwd-group-elements;
%unstructured-kwd-group.class;
%unstructured-kwd-group-elements;
Up/Down Rendition Class Elements parameter entitysee %subsup.class;
URI Attributes parameter entitysee %uri-atts;see %uri-atts;
URI Elements parameter entitysee %uri-elements;
URI for This Same Article Online
URLsee <ext-link>see <uri>
URL of this articlesee <self-uri>