upper left in pen and brown ink: N.; lower left in pen and brown ink: Palma Real. / Oreodoxia Regia. / Sta. Rosa-Mar. 21-1860.; by unknown hand across top verso in graphite: APG19252D.004.
- Ross, Zachary D. Charles De Wolf Brownell: A Decade of Travel, 1856-66. Exh. cat. Hirschl & Adler Galleries, Inc., New York, 2004: 9, no. 62.