Schele, Linda, and Peter Mathews. 1998. The Code of Kings: The Language of Seven Sacred Maya Temples and Tombs. New York: Scribner: 8: 73, Fig. 2.11
Schele, Linda, and David A. Freidel. 1990. A Forest of Kings: The Untold Story of the Ancient Maya. New York: William Morrow and Company, Inc.: 169, Fig. 5:2