Bibparse, biblex, and bibunlex are programs for doing syntax checking on BibTeX bibliography database files. Biblex lexically analyzes BibTeX bibliography database files and produces a lexical token stream from them. Bibparse verifies a biblex or bibclean (available as a separate package) lexical token stream or BibTeX database files. Bibunlex reconstructs a BibTeX bibliography database file from bibclean or biblex lexical analysis output. Also included in this package is bibdup which checks for duplicate abbreviations and entries in BibTeX bibliography database files.