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<ext-link> External Link

Link to an external file or resource.

Usage/Remarks

Use the standard XLink attributes to provide a live link to the external source. The attribute @xlink:href is not required, but should be used to provide the link.
Resource Type
The @ext-link-type attribute can be used to give an indication of the type of resource to which the external link points. While this Tag Set does not constrain the values of this attribute, and ordinary text is acceptable, the suggested values include:
ec
Enzyme nomenclature. See http://www.chem.qmw.ac.uk/iubmb/enzyme/
gen
GenBank identifier
genpept
Translated protein-encoding sequence database
highwire
HighWire Press intrajournal
pdb
Protein Data Bank. See https://www.rcsb.org/
pgr
Plant Gene Register. See https://www.ebi.ac.uk/~textman/pgr-htdocs/pgr/
pir
Protein Information Resource. See https://pir.georgetown.edu
pirdb
Protein Information Resource. See https://pir.georgetown.edu
pmcid
PubMed Central identifier
pmid
PubMed identifier
sprot
Swiss-Prot; now part of UniProt see https://www.ebi.ac.uk/uniprot/
aoi
Astronomical Object Identifier
doi
Digital Object Identifier
ftp
File transfer protocol
uri
Website or web service
Related Elements
<self-uri> is used when a document or document component (such as an article or a chapter) is available in multiple forms, for example, as a means of indicating the online version of a print document. Conversely, a URI that indicates a different book, article, or any other kind of live-linked external reference is usually tagged as <ext-link>. The <uri> element, although allowed everywhere <ext-link> is used, is more typically part of an address, information concerning a contributor, or part of a reference citation. Loosely put, an external link <ext-link> element is intended to act as a link; a URI <uri> element identifies a URI (such as a URL) in the text, but may or may not be a traversable link; and the <self-uri> points to another form of the same document. To make any of these elements into a live link, add the XLink @xlink:href attribute.
The address element <email> is allowed as part of a paragraph as well as inside an address. There are two ways to treat an email address in text: as an <email> element or as an <ext-link> element. If both a textual phrase (“the Moody Institute’s email address”) and a mailto URL are required, the <ext-link> element should be used.
The elements used in an address may include the address class elements: <addr-line>, <city>, <country>, <fax>, <institution>, <institution-wrap>, <state>, <phone>, and <postal-code> and the address linking class elements: <email>, <ext-link>, and <uri>.
Attributes
assigning-authority
ext-link-type
hreflang
specific-use

Base Attributes

id
xml:base
xml:lang

Linking Attributes

xlink:actuate
xlink:href
xlink:role
xlink:show
xlink:title
xlink:type

Namespaces

xmlns:xlink
Models and Context
May be contained in
<address>, <aff>, <alt-title>, <array>, <article-meta>, <article-title>, <attrib>, <bold>, <chapter-title>, <chem-struct>, <chem-struct-wrap>, <code>, <collab>, <comment>, <contrib>, <contrib-group>, <copyright-statement>, <corresp>, <data-title>, <def-head>, <disp-formula>, <disp-formula-group>, <element-citation>, <event-desc>, <fig>, <fig-group>, <fixed-case>, <front-stub>, <funding-statement>, <graphic>, <inline-media>, <inline-supplementary-material>, <italic>, <license-p>, <media>, <meta-value>, <mixed-citation>, <monospace>, <named-content>, <overline>, <p>, <part-title>, <preformat>, <product>, <publisher-loc>, <related-article>, <related-object>, <roman>, <sans-serif>, <sc>, <see>, <see-also>, <source>, <strike>, <styled-content>, <sub>, <subtitle>, <sup>, <supplementary-material>, <table-wrap>, <table-wrap-group>, <td>, <term>, <term-head>, <th>, <title>, <trans-source>, <trans-subtitle>, <trans-title>, <underline>
Description
Any combination of:
Content Model
<!ELEMENT  ext-link     (#PCDATA %ext-link-elements;)*               >
Expanded Content Model

(#PCDATA | bold | fixed-case | italic | monospace | overline | roman | sans-serif | sc | strike | underline | ruby | named-content | styled-content | sub | sup)*

Tagged Samples
Empty link
Display content must be generated.
...
<sec sec-type="intro">
 <title>Introduction</title>
 <p>... The highest 16S rDNA sequence similarity
  value of 98&#x0025; was obtained for the
  <italic>D. maris</italic> 16S rDNA sequence
  (GenBank accession no. <ext-link ext-link-type="gen"
  xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="Y18883"/>)
  and for the <italic>D. maris</italic> DSM 43672<sup>T</sup>
  16S rDNA sequence (GenBank accession no. <ext-link
  ext-link-type="gen" xmlns:xlink="http://www.w3.org/1999/xlink"
  xlink:href="X79290"/>) ...</p>
</sec>
...
Link with content 
...
<fig id="f1" orientation="portrait" position="float">
 <label>FIG. 1.</label>
 <caption>
  <p>(a) Schematic of the working principles of HFM, (b) a typical application
   scheme for an electric bias in HFM, (c) regulation the conformations and
   dynamics (trapping, concentration, and sudden stretching) of λ-DNA molecules
   in HFM, and (d) schematic of the trapping location regulation (enhanced online).
   [URL: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1063/1.4762852.1">
   http://dx.doi.org/10.1063/1.4762852.1</ext-link>]
   <alternatives>
    <media id="v1" mime-subtype="avi" mimetype="video" orientation="portrait"
      position="anchor" specific-use="original-format"
      xlink:href="v1-video1-orig.avi"/>
    <media mime-subtype="mpeg" mimetype="video" orientation="portrait"
      position="anchor" specific-use="archival-format"
      xlink:href="v1-video1-archive.mpeg"/>
    <media mime-subtype="x-flv" mimetype="video" orientation="portrait"
      position="anchor" specific-use="online-format"
      xlink:href="v1-video1-online.xfiv"/>
   </alternatives>
  </p>
 </caption>
 <graphic orientation="portrait" position="float" xlink:href="f1"/>
 <graphic id="f1a" orientation="portrait" position="float"
    xlink:href="dummy1.png"/>
 <graphic id="f1b" orientation="portrait" position="float"
    xlink:href="dummy2.png"/>
 <graphic id="f1c" orientation="portrait" position="float"
     xlink:href="dummy3.png"/>
 <graphic id="f1d" orientation="portrait" position="float"
     xlink:href="dummy4.png"/>
</fig>
...
Email link 
...
<contrib-group>
 <contrib contrib-type="author">
  <name name-style="western">
   <surname>Nüsslin</surname>
   <given-names>Fridtjof</given-names>
   <prefix>Dr.</prefix>
  </name>
 </contrib>
 <aff>Klinik für Strahlentherapie und Radiologische Onkologie,
  <institution>Technische Universität München</institution>, 
  Munich, Germany (Tel: 49-89-41404517, E-mail:
  <ext-link ext-link-type="email" xlink:href="mailto:nuesslin@lrz.tum.de">
  nuesslin@lrz.tum.de</ext-link>)</aff>
</contrib-group>
...
DOI (with @assigning-authority) 
...
<p>In <italic>Developing Thin Clients Using Amphibious Epistemologies</italic> 
 (<ext-link ext-link-type="doi" xlink:href="http://dx.doi.org/10.5555/12345679" 
 assigning-authority="crossref">http://dx.doi.org/10.5555/12345679</ext-link>), 
 Josiah Carberry introduced &ldquo;Entrust,&rdquo; a linear-time tool for 
 simulating architecture.</p>
...
To Clinical Trial 
...
<p>... Trial registration: <ext-link 
 ext-link-type="clinical trials" 
 xlink:href="NCT02442440">NCT02442440</ext-link> 
 (<ext-link ext-link-type="uri" 
    xlink:href="https://register.clinicaltrials.gov"
   >https://register.clinicaltrials.gov</ext-link>)
 ...</p>
...