Returns all the biblioentry or bibliomixed elements that have an abbrev that matches a citation. The internal bibliography of the input document is always taken into account.

In the form with only one argument, external bibliographies are also taken into account if they are designated in the input document with a <?db biblioary-collection='URIs'?> processing instruction. In the form with two arguments, you can specify a list of URIs of the external bibliographies.

When more than one entry is found, the result sequence will start with entries from the internal bibliography, if any.

The function is designed so that it can be used independently from the xslTNG stylesheets. You can, for example, integrate it in a Schematron rule that checks whether every citation has exactly one corresponding bibliographic entry while authoring your document.