Computer Systems Research Group
From Computer History Wiki
The University of California at Berkeley's Computer Systems Research Group (CSRG is the usual short form of the name) is is the group that was responsible for CSRG BSD. (Not to mention biff, vi, and of course sendmail.)
Notable people include Eric Allman, Marshall Kirk McKusick, Bill Joy.
An excellent overview of the history of the CSRG, as told by Marshall Kirk McKusick is available here.
CD
Kirk has released CD sets containing as much of the work of the CSRG as possible. You can download ISO's of them here.