Fred Sandback, Study for a Sculpture, 1971, Pencil and white ink on colored paper, The Museum of Modern Art, New York. https://dartabase.art/cite/moma/36121

Fred Sandback, Project for Cologne, 1976, Pencil and felt-tip pen on paper, The Museum of Modern Art, New York. https://dartabase.art/cite/moma/37003

Fred Sandback, Project for Cologne, 1976, Pencil and felt-tip pen on paper, The Museum of Modern Art, New York. https://dartabase.art/cite/moma/37007

Fred Sandback, Project for Cologne, 1976, Pencil and felt-tip pen on paper, The Museum of Modern Art, New York. https://dartabase.art/cite/moma/37011