Object Identifier


Used to record an identifier, such as a DOI, for elements other than the top-level element <article>, for example, for the elements <abstract> or <fig>


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.


content-type Type of Content
pub-id-type Type of Publication Identifier

Model Information

Content Model

<!ELEMENT  object-id    (#PCDATA)                                    >


Text, numbers, or special characters

This element may be contained in:

<boxed-text> Boxed Text; <chem-struct-wrapper> Chemical Structure Wrapper; <citation> Citation; <fig> Figure; <graphic> Graphic; <media> Media Object; <product> Product Information; <related-article> Related Article Information; <supplementary-material> Supplementary Material; <table-wrap> Table Wrapper

Tagged Example

<sec sec-type="results">
<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">
<p>Deaths among patients receiving day hospital care 
or alternative services. Odds ratios of death by end 
of follow up were calculated by fixed effects model. 
Heterogeneity between trials is presented as 
<alt-text>Deaths in hospitals or with alternative services</alt-text>
<graphic xmlns:xlink="http://www.w3.org/1999/xlink" 
xlink:href="fors2662.f1" alt-version="yes">