How many movies have Manfred Spies and Wolf C. Hartwig collaborated on?

They have worked on 3 movies together! Their first movie together was Schoolgirl Report Part 5: What All Parents Should Know (1973) while their highest rated movie together was 14 and Under (1973). They have not worked together since Schoolgirl Report Part 7: What The Heart Must Thereby… (1974). They are most known for their drama films together.