Object Identifier

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.

The Archiving and Interchange Tag Set includes two elements which may be used to record a DOI as an identifier: <object-id> and <pub-id>. The <object-id> is used to identify parts of an article, for example, a particular section, a figure, a table, or even a specific citation (as an entity) in the article’s bibliographic reference list. The <pub-id> element is used inside a citation to identify a cited publication. Consequently, a bibliographic reference (<element-citation> or <mixed-citation> could contain both the <object-id> element (with the DOI for that citation) and the <pub-id> element (with the DOI for the journal being referenced in the citation) as shown by the example below:

  <front> ...
      <article-id pub-id-type="doi">MyPub.20070215.03154</article-id>
    <ref-list> ...
      <ref id="B6"><label>6</label> 
          <object-id pub-id-type="doi"
      <ref id="B7"><label>7</label> 
          <object-id pub-id-type="doi" 
          <person-group person-group-type="author"> 
          <name><surname>Brook</surname> <given-names>I.</given-names>
          <article-title>Infant Botulism</article-title> 
          <source>J Perinatol.</source><year>2007</year> 
          <pub-id pub-id-type="pmid">17314986</pub-id> 
          <pub-id pub-id-type="doi">10.1038/sj.jp.7211651</pub-id> 
      <ref id="B8"><label>8</label> 
          <object-id pub-id-type="doi" 
      <ref id="B9"><label>9</label> 
          <object-id pub-id-type="doi"


content-type Type of Content
pub-id-type Type of Publication Identifier
specific-use Specific Use

Content Model

<!ELEMENT  object-id    (#PCDATA)                                    >


Text, numbers, or special characters

This element may be contained in:

<abstract>, <boxed-text>, <chem-struct>, <chem-struct-wrap>, <element-citation>, <fig>, <graphic>, <media>, <mixed-citation>, <product>, <related-article>, <related-object>, <supplementary-material>, <table-wrap>


<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">
<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
<alt-text>Deaths in hospitals or with alternative services</alt-text>
<graphic xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="fors2662.f1"  >