lower left in graphite: 32-XXXV; lower right in graphite: Drewes - 1944; lower left edge in graphite: INNER TROPICAL SEAS
(Wolfe Street Gallery, Alexandria, VA); Jacob Kainen, Washington, D.C., purchased April 19, 1976; gift to NGA, 2002.
- Rose, Ingrid. Werner Drewes: A Catalogue Raisonné of His Prints. Munich and New York: Verlag Kunstgalerie Esslingen, 1984, sec. III, p. 323, no. 120.