Prats, J.J. "Lt. William Lewis". The Historical Marker Database. J.J. Prats. Archived from the original on November 9, 2011. Retrieved September 15, 2009.
Zontine, Patricia (April 2009). "Lt. William Lewis". Monticello. org. Thomas Jefferson Foundation, Inc. Archived from the original on October 9, 2009. Retrieved July 10, 2009.
Denslow, William R. (1957). "10,000 Famous Freemasons". Macoy Publishing & Masonic Supply Co., Inc. Archived from the original on June 15, 2007. Retrieved February 19, 2017.
"Bicentennial Lewis & Clark Expedition Issue", Arago: people, postage & the post, National Postal Museum online, viewed April 28, 2014. An image of the stamp can be seen at Arago.si.edu, 37c Lewis and Clark on Hill stamp
Prats, J.J. "Lt. William Lewis". The Historical Marker Database. J.J. Prats. Archived from the original on November 9, 2011. Retrieved September 15, 2009.
Zontine, Patricia (April 2009). "Lt. William Lewis". Monticello. org. Thomas Jefferson Foundation, Inc. Archived from the original on October 9, 2009. Retrieved July 10, 2009.
"Lt. William Lewis". Monticello.org. Archived from the original on October 9, 2009. Retrieved August 13, 2012.
Denslow, William R. (1957). "10,000 Famous Freemasons". Macoy Publishing & Masonic Supply Co., Inc. Archived from the original on June 15, 2007. Retrieved February 19, 2017.
Lewis, M. (1814). History of the Expedition Under the Command of Lewis and Clark. Philadelphia: Bradford and Inskeep. OCLC11603043.
Cutright 1986. Cutright, P. R. (March 1986). "Rest, Rest, Perturbed Spirit". We Proceeded On. 12 (1). Portland: Lewis and Clark Trail Heritage Foundation: 7–17. ISSN0275-6706.