Blumberg, Rhoda. The Incredible Journey of Lewis and Clark.  New York City. Lothrop, Lee & Shepard Books, 1987.

Cook, Fredrick. “Continental Divide.” World Book 2001, 2001.  

Faber, Doris. American Government. New York: Macmillan Publishing Company, 1988.

Moss, Joyce. Profiles in American History. New York: Gale Research Incorporated, 1995.

Moulton, Gary. “Clark, William.” World Book 2001, 2001.

Scheller, William. The World’s Greatest Explorers. Minneapolis: Oliver Pres Incorporated, 1992.   

William Clark Biography. [Online] available http://www.edgate.com/lewisanclark/bios/BIO_W_clark.html October 2, 2006.