Photo, 1957 Yves Klein in front of his Sponge Sculpture at the exhibition "Monochrome Propositions of Yves Klein" Gallery One, London
Photo, 1959 Yves Klein, Iris Clert and Rotraut at the opening of the exhibition "Bas-reliefs in a sponge forest", Galerie Iris Clert
Photo, ca. 1960 Yves Klein and Rotraut with Ci-gît l'Espace [Here Lies Space] (RP 3) and the Sponge Relief (RE 20)
Photo, january 14th 1961 Yves Klein surrounded by Sponge Sculptures during the exhibition "Monochrome und Feuer", Museum Haus Lange