How many movies have Helma Keller and Kathleen Warners collaborated on?

They have worked on 2 movies together! Their first movie together was Claudia de Breij: Hete Vrede (2012) while their highest rated movie together was Van der Laan & Woe: Superlatief (2012). They have not worked together since Van der Laan & Woe: Superlatief (2012).