How many movies have Gert Wilden and Walter Boos collaborated on?

They have worked on 8 movies together! Their first movie together was Schoolgirl Report Part 1: What Parents Don't Think Is Possible (1970) while their highest rated movie together was Schoolgirl Report Part 10: Every Girl Starts Sometime... (1976). They have not worked together since Schoolgirl Report Part 12: If Mom Only Knew... (1978). They are most known for their drama films together.