Any element with an XML Unique Identifier may be cross-referenced using a Cross-Reference element; generally, this is all that is necessary to generate a cross-reference, since several of these elements (including Figure, Equation and Table) receive labels automatically, and when they do not, there may be a Title that can be used.

On occasion, however, it may be useful or necessary to provide text for a cross-reference label explicitly; for these cases, use this attribute.

In particular, any Bibliographic Entry element that is referenced from the text using a Cross-Reference should be provided with a Cross-Reference Label.