upper left verso in colored pencil: No 38; upper left verso in graphite: No 2; upper right verso in felt tip pen: Canova / 150; upper right verso in pen and ink: 28424 Antonio Canova; by later hand, lower left verso in paint: Bison
- Art for the Nation: Gifts in Honor of the 50th Anniversary of the National Gallery of Art. Exh. cat. National Gallery of Art, Washington, 1991: p.118.