A Tex extension package for bibliographic citations, distributed with LaTeX. BibTeX uses a style-independent bibliography database (.bib file) to produce a list of sources, in a customisable style, from citations in a Latex document. It also supports some other formats.
BibTeX is a separate program from LaTeX. LaTeX writes information about citations and which .bib files to use in a ".aux" file. BibTeX reads this file and outputs a ".bbl" file containing LaTeX commands to produce the source list. You must then run LaTeX again to incorporate the source list in your document. In typeset documents, "BibTeX" is written in upper case, with the "IB" slightly smaller and with the "E" as a subscript. BibTeX is described in the LaTeX book by Lamport.