The following, in order:

• <article-id> Article Identifier, zero or more

• <article-categories> Article Grouping Data, zero or one

• <title-group> Title Group, zero or one

• Any combination of:

  • <contrib-group> Contributor Group

  • <aff> Affiliation

  • <aff-alternatives> Affiliation Alternatives

  • <x> X - Generated Text and Punctuation

• <author-notes> Author Note Group, zero or one

• <pub-date> Publication Date, zero or more

• <volume> Volume Number, zero or one

• <volume-id> Volume Identifier, zero or more

• <volume-series> Volume Series, zero or one

• <issue> Issue Number, zero or more

• <issue-id> Issue Identifier, zero or more

• <issue-title> Issue Title, zero or more

• <issue-sponsor> Issue Sponsor, zero or more

• <issue-part> Issue Part, zero or one

• <isbn> ISBN, zero or more

• <supplement> Supplement Information, zero or one

• Optionally any one of:

  • The following, in order:

    • Optionally, the following sequence (in order):

      • <fpage> First Page

      • <lpage> Last Page, zero or one

    • <page-range> Page Ranges, zero or one

  • <elocation-id> Electronic Location Identifier

• Any combination of:

  • <email> Email Address

  • <ext-link> External Link

  • <uri> Uniform Resource Indicator (URI)

  • <product> Product Information

  • <supplementary-material> Supplementary Material

• <history> History: Document History, zero or one

• <permissions> Permissions, zero or one

• <self-uri> URI for This Same Article Online, zero or more

• <related-article> Related Article Information, zero or more

• <abstract> Abstract, zero or more

• <trans-abstract> Translated Abstract, zero or more

• <kwd-group> Keyword Group, zero or more

• <funding-group> Funding Group, zero or more

• <conference> Conference Information, zero or more

• <counts> Counts, zero or one

• <custom-meta-group> Custom Metadata Group, zero or one