FreeBSD PPP & SLIP Handbook, http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/ppp-and-slip.html
A Powerline Introduction website, http://www.ipcf.org/powerlineintro.html
The Linux ATM Project website, http://linux-atm.sourceforge.net
DaemonNews Article "Building an ATM Firewall with BSD," http://www.daemonnews.org/200003atmfirewall.html
The Host ATM Research Platform (HARP) website, http://www.msci.magic.net/harp/
Supported FreeBSD ATM interfaces website, http://www.freebsd.org/releases/4.9R/hardware-i386.html#AEN1352
Sangoma Technologies Corp. website, http://www.sangoma.com
Prosum website, http://www.prosum.net
Marconi website, http://www.marconi.com
Project mpd, which is a FreeBSD PPP daemon based on the Netgraph facility, http://sourceforge.net/projects/mpd/