Unique identifier (such as a DOI or URI) for a component within an article (for example, for a figure or a table).
Such an identifier may be created by a publisher or archive, and there is no requirement that identifiers be unique.
Design Note: An element, rather than an attribute, was chosen as the means to capture DOIs and other identifiers so multiple identifiers could be retained.
<!ELEMENT object-id (#PCDATA) >
Text, numbers, or special characters
<boxed-text>, <chem-struct-wrap>, <element-citation>, <fig>, <graphic>, <media>, <mixed-citation>, <product>, <related-article>, <related-object>, <supplementary-material>, <table-wrap>
...
<sec sec-type="results">
<title>Results</title>
<p>We identified 703 abstracts, of which 687 were not
relevant ... Details of randomisation procedures,
treatment schedules, and numbers of patients followed up
are given on the <italic>BMJ</italic> website.</p>
<fig id="F1">
<caption>
<title>Deaths among patients receiving day hospital care
or alternative services.</title><p>Odds ratios of death by end
of follow up were calculated by fixed effects model.
Heterogeneity between trials is presented as
χ<sup>2</sup></p>
</caption>
<alt-text>Deaths in hospitals or with alternative services</alt-text>
<graphic xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="fors2662.f1">
<object-id>456472</object-id>
</graphic>
</fig>
...
</sec>
...
JATS-common1.ent