Originally set up to support Unix internally, the Unix Support Group eventually became Unix System Laboratories, and developed the System III and System V commercial versions of Unix.
1973:
USG Release 1.0
1974:
USG Release 2.0
1975:
MERT First Edition
1976:
Program Generic Issue 2
1977:
Program Generic Issue 3
1978:
UNIX/TS
1979:
CB-UNIX
1980:
System III
1981:
UNIX Release 4
1982:
UNIX Release 5
1983:
System V