[1] Siminski, P. 2005. Census Report as of 31/12/2004. Email from Peter Siminski, Director of Collections, Arizona-Sonora Desert Museum, August 10, 2005
[2] Robinson, M. 2005. Wild Mexican gray wolves in the U.S. and Mexico, 1920-2005. Email from Michael Robinson, Center for Biological Diversity, August 1, 2005.