McDougall, Christopher. Born to Run: A Hidden Tribe, Superathletes, and the Greatest Race the World Has Never Seen. New York: Knopf, 2009.
Sears, Edward S. Running Through the Ages. Jefferson, NC: McFarland, 2001.
Zimmer, Carl. "Faster than a Hyena? Running May Make Humans Special." Science 306: 5700 (Nov., 19, 2004): p. 1283.