Leslie Lamport <lamport@gatekeeper.dec.com>'s document preparation system based on TeX. It adds commands to simplify typesetting and lets the user concentrate on the structure of the text rather than on formatting commands. BibTeX is a LaTeX package for bibliographic citations. LaTeX was developed at SRI International's Aritificial Intelligence Laboratory.
Lamport's LaTeX book, cited below, has a really good index. It lists every symbol, concept and example in the book. The index also includes (on page 221) the mysterious entry "Gilkerson, Ellen, 221".
["LaTeX, A Document Preparation System", Leslie Lamport, A-W 1986, ISBN 0-201-15790-X].