1997 IUCN red list of threatened plants (1997)

American fern journal - American Fern Society. (American Fern Society, 2002)

Catalogue of the vascular plants of Ecuador = Catálogo de las plantas vasculares del Ecuador - González, Amada Pedroni. (Missouri Botanical Garden Press, 1999)

Fieldiana. Botany - Field Museum of Natural History. (Chicago Natural History Museum, 1989)

Fieldiana. Botany - Field Museum of Natural History. (Chicago Natural History Museum, 1989)

Fieldiana. Botany - Field Museum of Natural History. (Chicago Natural History Museum, 1989)