3 Public Domain TEXware
TEX is a widely used typesetting system and many people freely share their
software efforts related to TEX.
Many programs, macros, and other accessories for TEX are available on the
Internet via FTP to the CTAN (Comprehensive TEX Archive Network)
archive, and if you are a serious TEX user
you will find much valuable software there:
ftp://ctan.tug.org/tex-archive