The Cactaceae : descriptions and illustrations of plants of the cactus family - Britton, Nathaniel Lord, 1859 -1934 (Carnegie Institution of Washington, 1919)

Carnegie Institution of Washington publication - Carnegie Institution of Washington (Carnegie Institution of Washington, 1919)

Carnegie Institution of Washington publication - Carnegie Institution of Washington (Carnegie Institution of Washington, 1919)

Contributions from the United States National Herbarium - United States. National Herbarium. (Smithsonian Institution Press, 1920)

Monatsschrift für Kakteenkunde (J. Neumann, 1913)

Monatsschrift für Kakteenkunde (J. Neumann, 1913)

Trees and shrubs of Mexico - Standley, Paul Carpenter, 1884 -1963 (Govt. Print. Off, 1924)