How many movies have Gunter Otto and Mike Silver collaborated on?

They have worked on 2 movies together! Their first movie together was Heidi 5: Heidi und die lustigen Spritzbuben der Berge (1992) while their highest rated movie together was Heidi 6: Heidi lässt sie alle jodeln (1993). They have not worked together since Heidi 6: Heidi lässt sie alle jodeln (1993).