Frost, Darrel R. (2013). Ascaphus Stejneger, 1899. Amphibian Species of the World 5.6, an Online Reference. American Museum of Natural History. Alirita 7a de Julio 2013.
Frost, Darrel R. (2013). Ascaphidae Fejérváry, 1923. Amphibian Species of the World 5.6, an Online Reference. American Museum of Natural History. Alirita 7a de Julio 2013.