How many movies have Gregory H. Watkins and Hal Harrison collaborated on?

They have worked on 5 movies together! Their first movie together was Perry Mason: The Case of the Murdered Madam (1987) while their highest rated movie together was Perry Mason: The Case of the Avenging Ace (1988). They have not worked together since Perry Mason: The Case of the Lethal Lesson (1989). They are most known for their tv movie films together.