How many movies have Carlos Piaggio and Helvio Soto collaborated on?

They have worked on 4 movies together! Their first movie together was Érase un niño, un guerrillero, un caballo… (1967) while their highest rated movie together was Bloody Nitrate (1969). They have not worked together since Metamorphosis of the Chief of the Political Police (1973). They are most known for their drama films together.