Document, 1961 Invitation card for the exhibition "Yves Klein Monochrome und Feuer" at the Museum Haus Lange in Krefeld
Document, 1964 Invitation card for the exhibition "Yves Klein Peintures de feu" at the Galerie Schmela, Düsseldorf
Article, 1961, Roland F. Pease Jr. Testimonial of Roland F. Pease Jr. on the blue monochromes seen at the Leo Castelli exhibition, 1961