This enhancement request is for JATS XML exports that use the numeric <sup> JATS XML element like Cell & Nature to group citations instead of parentheses. The main reasoning behind this is to minimize how much citation style formatting is being set in the XML and only save information that serves a dual role of being both:

• presentation XML (for reader implementations that do nothing more than echo the numeric superscript style)
• and/or minimal semantic information (for reader implementations that can re-style citations).

This is related to issue #1462.

Currently, markdown such as:

There are examples [@jats_authoring; @ref-enwikiu003ajats]

results in a JATS XML export like

<p>There are examples (<xref ref-type="bibr" rid="ref-1">U.S. National Library of Medicine (NLM), 2024</xref>; <xref ref-type="bibr" rid="ref-2">contributors, 2023</xref>).</p>

So with this enhancement the JATS XML export would instead be:

<p>There are examples<sup><xref ref-type="bibr" rid="ref-1">1</xref>,<xref ref-type="bibr" rid="ref-2">2</xref></sup>.</p>

Both the existing implementation's use of parentheses and this enhancement's use of <sup> are used by JATS XML in the PubMed Central Open Access Subset. The numeric <sup> style matches the Citation Language Style of

<style xmlns="http://purl.org/net/xbiblio/csl" class="in-text" version="1.0">
...
  <citation>
    <sort>
      <key variable="citation-number"/>
    </sort>
    <layout vertical-align="sup" delimiter=",">
        <text variable="citation-number"/>
    </layout>
  </citation>
...

which are found in the cell.csl and nature.csl files of the https://www.zotero.org/styles and https://github.com/citation-style-language/styles.

Using the above CSL and style is supported by pandoc and will output the JATS XML in this enhancement request. This is how https://gitlab.com/perm.pub/baseprinter uses 'pandoc'.

This enhancement will also increase interoperability with the https://gitlab.com/perm.pub/epijats JATS XML parser and related tools. Currently, epijats will recognize <sup><xref ... as a citation group but is not as smart as npm jats-xml to parse the parenthetical style semantically.

It is too bad JATS XML does not have a citation group XML element. The defacto closest to one is a rather hacky <sup> in the style described in this enhancement.