SDF is a freely available documentation system designed and developed by Ian
Clatworthy, with help from many others. Based on a simple, readable markup
language, SDF generates high quality output in multiple formats, all derived
from a single document source. Supported output formats include HTML,
PostScript, PDF, man pages, POD, LaTeX, SGML, MIMS HTX and F6 help, MIF, RTF,
Windows help and plain text.