lower left in graphite: Samuel Clemens; lower center in graphite: Artist's Proof; lower right in graphite: Jacob Landau
Jay Finkel, Washington, DC; acquired 2013 by the National Gallery of Art
- Flint, Janet. Jacob Landau: The Graphic Work. Trenton: New Jersey State Museum, 1983, no. 59.2.
- Windisch, Gail, and Sylvan Cole, Jr. Art for Every Home: An Illustrated Index of Associated American Artists Prints, Ceramics, and Textile Designs. Manhattan: Marianna Kistler Beach Museum of Art, Kansas State University, 2016, p. 179, no. 1619.