ftp://ftp.uu.net/doc/lpf/ UUNet archive of LPF documents
(Warning - the old "lpf.org" domain has been taken over by the
Libertarian party in Florida.)
(The LPF seems to be stirring after many months of inactivity.)
http://www.hifn.com/ HI/fn now has all of the rights
to the STAC and MS-PPC compression algorithms, and sells source code
and compression chips for PPP implementations. The old STAC Electronics
site still exists, but has no compression references.