(15 Oct 1990) – Season 4 Episode 4 (Serial 176)

#82 – Release: 18 Apr 1975

(8 Oct 1990) – Season 4 Episode 3 (Serial 177)

(1 Oct 1990) – Season 4 Episode 2 (Serial 178)

#81 – Release: 29 Apr 1981

(24 Sep 1990) – Season 4 Episode 1 (Serial 175)

#80 – Release: 29 Sep 1986

(18 Jun 1990) – Season 3 Episode 26 (Serial 174)

#79 – Release: 20 Jul 1981

(4 Jun 1990) – Season 3 Episode 25 (Serial 173)