ZT/Le savant Circa 1984 Title Year Constant | Aquarellen 1987 1987 CONSTANT-nieuwe aquarellen 1984 Title Year Constant. Les Aquarelles 1994
ZT/Cobraschilder Title Year Aquarellen en tekeningen 1978 Title Year Constant. Les trois espaces 1992
De vogelman Title Year Cobra, la couleur spontanée 2018 Cobra, la couleur spontanée 2017 The Avant-Garde Won’t Give Up 2015 Cobra, post Cobra 1991 Title Year The Avant-garde Won't Give Up 2017