Düsseldorf
I-S LXX a, 1970
Price on Request
Hommage au Carré, 1965
GB 1, 1969
Homage to the Square: Edition Keller Ik, 1970
I-S j, 1973
I-S e, 1970
Hommage au carré, 1965
Allegro, 1961
SP XI, 1967
SP V, 1967
SP IX, 1967
SP-J, 1971
SP VII, 1967
