Photo, janvier 1961 Yves Klein next to a Sponge Relief (RE 10) lors de son exposition "Yves Klein Monochrome und Feuer", Museum Haus Lange
Photo, ca. 1960 Yves Klein and Rotraut with Ci-gît l'Espace [Here Lies Space] (RP 3) and the Sponge Relief (RE 20)
Photo, 1959 International collaboration between artists and architects in the realisation of the new Gelsenkirchen Opera House
Photo, 1959 Inauguration of the Gelsenkirchen Opera Theater in the presence of Jean Tinguely and Yves Klein