References- Thank you!

Bartlett, R. D., and Patricia P. Bartlett. 2006. Guide and Reference to the
    Amphibians of Eastern and Central North America (North of              
    Mexico). Gainesville, FL, University Press of Florida.

Campbell, N., Reece, J. 2008. Biology. 8th Ed. San Francisco, California;   
    Pearson Education, Inc.

Garner, Trenton W. J., et al. 2006. “The emerging amphibian pathogen
    Batrachochytrium dendrobatidis globally infects introduced    
    populations of the North American bullfrog, Rana catesbeiana.”
    Biology Letters. London Royal Society Publishing <URL:
    garner-2006.pdf>. Accessed 23 March 2010.

Leviton, Alan E. 1971. Reptiles and Amphibians of North America. New
    York Doubleday & Company, Inc.

Sheldon, Allen Blake. 2006. Amphibians & Reptiles of the North Woods.
Kollath and Stensaas Publications.

Stebbins, Robert C., and Nathan W. Cohen. 1995.  A Natural History of
. Princeton, Princeton University Press.

 Internet Sources:

Williams, A. <URL:
    catesbeiana.htm>. Accessed 15 April 2010.

n.a. 2008.
    Accessed 17 April 2010.

For further reading on the American Bullfrog visit:

The National Geographic website:

The Animal Diversity Web website:

The California Reptiles & Amphibians website: