External links

Capture external links using a ext-link element.

Capture a xlink:href attribute to point to the external resource that is being linked.

Wherever possible use a fully qualified DOI for external links.

Capture a ext-link-type attribute with a value from the following list.

doi
ftp
gen
orcid
pmcid
pmid
uri

The value of xlink:href must start with http:// or https:// for all ext-link-type attribute values except gen (see GenBank example below) and ftp.

Capture a DOI in the body text of a book or journal article in an ext-link> element whose @ext-link-type attribute has the value uri. Give the xlink:href attribute the value https://doi.org/ followed by the DOI.

For a link within the body of a journal article to a related article in the same journal (for corrections, letters, editorials and commentaries), follow the instructions for capturing a related article in the body.

If the text of the link is to be typographically styled (e.g. italic, superscript), capture the typographic markup (e.g. italic, sup) within the ext-link element.

DOI link

The xlink:href value for a DOI link consists of https://doi.org/ followed by the DOI itself. The value of ext-link may be the DOI itself, or the full link

<mixed-citation publication-type="journal">
  <person-group person-group-type="author">
    <string-name><surname>Schmaltz</surname>, <given-names>Rodney M.</given-names></string-name>, &amp;
    <string-name><surname>Enström</surname>, <given-names>Rickard</given-names></string-name>
  </person-group>.
  (<year>2014</year>, <month>October</month> <day>8</day>). 
  <article-title>Death to weak PowerPoint: Strategies to 
    create effective visual presentations</article-title>.
  <source>Frontiers in Psychology</source>, <volume>5</volume>, <fpage>1138</fpage>. 
  doi:<ext-link ext-link-type="uri" xlink:href="https://doi.org/10.3389/fpsyg.2014.01138">10.3389/fpsyg.2014.01138</ext-link>
</mixed-citation>

GenBank link

A GenBank link must follow the format of this example.

<ext-link ext-link-type="gen" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="Y18883">Y18883</ext-link>

PubMed link

Append the PubMed ID to https://www.ncbi.nlm.nih.gov/pubmed/ to construct the xlink:href value.

<mixed-citation publication-type="book">
  <collab>U.S. Department of Health and Human Services OotSG</collab>. 
  <source>The Surgeon General's Call to Action to Support Breastfeeding</source>. 
  <year>2011</year>. 
  Pubmed ID: <ext-link ext-link-type="pmid" xlink:href="https://www.ncbi.nlm.nih.gov/pubmed/21452448">21452448</ext-link>.
</mixed-citation>

FTP link

The value of xlink:href must start with ftp://

<ext-link ext-link-type="ftp" 
  xlink:href="ftp://ftp.pmodwrc.ch/pub/data/irradiance/virgo/TSI/korr_tot6_001_0804.dat">
    ftp://ftp.pmodwrc.ch/pub/data/irradiance/virgo/TSI/korr_tot6_001_0804.dat
</ext-link>