Simpson, D. R., & Janos, D. (1972). A punch card key to the families of dicotyledons of the western hemisphere south of the United States. Chicago, Illinois: Field Museum of Natural History.
Chicago Style CitationSimpson, Donald R., and David Janos. A Punch Card Key to the Families of Dicotyledons of the Western Hemisphere South of the United States. Chicago, Illinois: Field Museum of Natural History, 1972.
MLA CitationSimpson, Donald R., and David Janos. A Punch Card Key to the Families of Dicotyledons of the Western Hemisphere South of the United States. Chicago, Illinois: Field Museum of Natural History, 1972.
Warning: These citations may not always be 100% accurate.