How many movies have Christopher Cerf and Martin P. Robinson collaborated on?

They have worked on 2 movies together! Their first movie together was Sesame Street: Sleepytime Songs & Stories (1986) while their highest rated movie together was Sesame Street: Put Down the Duckie: An All-Star Musical Special (1988). They have not worked together since Sesame Street: Put Down the Duckie: An All-Star Musical Special (1988).