Montana
Historical Society Voyages of Discovery: Essays on the Lewis and Clark
Expedition
Ronda, James P, Montana Historical Society Press1998
Britannica.com
Inc. Online Reference Sources 2000-2001
Historical and Biographical Information Resources
United
States Library of Congress Maps Division
A map of Lewis and Clark's track, across the western portion of North America
from the Mississippi to the Pacific Ocean : by order of the executive of the
United States in 1804, 5 & 6 Philadelphia : Bradford and Inskeep, 1814