Cross References

TEI provides three elements for cross references that we use.

• <xr> (cross-reference phrase) contains a phrase, sentence, or icon referring the reader to some other location in this or another text. May contain character data and phrase-level elements; usually contains a <ref> or a <ptr> element. This element encloses both the actual indication of the location referred to, which may be tagged using the <ref> or <ptr> elements, and any accompanying material which gives more information about why the reader is being referred there.
• <ref> (reference) defines a reference to another location, possibly modified by additional text or comment.
• <ptr> (pointer) empty element that defines a pointer to another location. Cannot contain any additional text (so generally unsuitable for Nineteenth-Century Knowledge Project cross references).
• @target specifies the destination of the reference by supplying one or more URI references.

Usage of the <xr> is preferred (example 1), to capture the context of the cross reference. Where that is not feasible, using a <ref> element alone is legitimate (example 2).

1. <xr>See especially <ref target="#SEC12">section 12 on page 34</ref>.</xr>

2. See <ref target="kp-eb0703-0123-0095-01">Shipbuilding</ref>.