BibTeX provides an easy to use means to integrate citations and
bibliographies into LaTeX documents. But the user is left alone
with the management of the BibTeX files. The program BibTool is
intended to fill this gap. BibTool allows the manipulation of BibTeX
files which goes beyond the possibilities---and intentions---of
BibTeX.

BibTool contains a user's manual written in LaTeX of more than 60
pages (and still growing).

Homepage:
http://www.gerd-neugebauer.de/software/TeX/BibTool.en.html
