Photo, 1961 Paul Wember, Rotraut Uecker and Yves Klein in front of "Column of Fire" during the exhibition "Yves Klein Monochrome und Feuer" at the Museum Haus Lange
Article, 1961, Roland F. Pease Jr. Testimonial of Roland F. Pease Jr. on the blue monochromes seen at the Leo Castelli exhibition, 1961