Suppose bibliographic entries in Figure C 14.23 contain a mandatory key element, and that other documents can contain matching cite elements. Create an XSLT script that imitates the work of BibTEX. Your script should

(a) Read an XML document, find all the cite elements, collect the keys they contain, and replace them with bibref elements that contain small integers instead.

(b) Read a separate XML bibliography document, extract the entries with matching keys, and write them, in sorted order, to a new (and probably smaller) bibliography.

The small numbers in the bibref elements of the new document from (a) should match the corresponding numbered entries in the new bibliography from (b).