For distribution maps of Washington reptiles, see Washington Gap Analysis.
For keys to identifying adult salamanders and frogs of Washington, visit the Slater Museum Web page at the University of Puget Sound in Tacoma.
For a great key to identifying tadpoles, see Tadpoles of the United States and Canada: A Tutorial and Key.
Online taxonomic reference of Amphibian Species of the World at the American Museum of Natural History
Smithsonian Institution's bibliography on the biology of amphibians and reptiles
The Tree of Life phylogeny of living amphibians.