Attribute: xmlns:xlink
Value: CDATA
May be in elements:
- <abbrev>
- <bio>
- <chem-struct>
- <collab>
- <contrib>
- <element-citation>
- <email>
- <ext-link>
- <funding-source>
- <graphic>
- <inline-graphic>
- <inline-supplementary-material>
- <institution>
- <license>
- <media>
- <mixed-citation>
- <named-content>
- <nlm-citation>
- <product>
- <related-article>
- <self-uri>
- <supplementary-material>
- <uri>