Paul Kelpe, Composition, Number 160, 1928, Watercolor, pencil, and cut-and-pasted paper on paper, The Museum of Modern Art, New York. https://dartabase.art/cite/moma/36501

Paul Kelpe, Composition, Number 337, 1933, Watercolor and pencil on paper, The Museum of Modern Art, New York. https://dartabase.art/cite/moma/36505