created by (65 episodes, 1971-2001)
story by (4 episodes, 1972-1973)
creator (1 episode, 2003)
story (1 episode, 1990)
written by (1 episode, 1971)
written by (5 episodes, 1971-1992)
story by (4 episodes, 1972-1975)
teleplay by (4 episodes, 1972-1973)
written by (7 episodes, 1974-1995)
story by (1 episode, 1976)
teleplay by (1 episode, 1974)
teleplay by (5 episodes, 1971-1974)
written by (2 episodes, 1971-1990)
teleplay by (2 episodes, 1973-1974)
(2 episodes, 1972-1974)
story by (3 episodes, 1973-1974)
written by (2 episodes, 1975)
story by (1 episode, 1975)
teleplay by (1 episode, 1975)
teleplay by (1 episode, 1992)
(2 episodes, 1978-1992)
written by (1 episode, 1978)
written by (3 episodes, 1989-1991)
written by (2 episodes, 1990-1991)
story by (1 episode, 1990)
teleplay by (1 episode, 1990)
written by (2 episodes, 1971-1972)
story by (1 episode, 1974)
teleplay by (1 episode, 1973)
written by (2 episodes, 1974-1978)
teleplay by (2 episodes, 1975-1976)
teleplay by (2 episodes, 1976)
teleplay by (1 episode, 2001)
(1 episode, 1998-2001)
story by (1 episode, 1971)
story by (1 episode, 1972)
written by (1 episode, 1972)
story by (1 episode, 1973)
written by (1 episode, 1973)
written by (1 episode, 1975)
written by (1 episode, 1976)
teleplay by (1 episode, 1977)
story by (1 episode, 1977)
written by (1 episode, 1977)
story by (1 episode, 1978)
teleplay by (1 episode, 1978)
based on an idea by (1 episode, 1978)
written by (1 episode, 1989)
written by (1 episode, 1991)
story by (1 episode, 1992)
written by (1 episode, 1993)
written by (1 episode, 1997)
written by (1 episode, 1998)
story by (1 episode, 2001)
written by (1 episode, 2003)