-Animal Diversity Web.
  University of Michigan
 Museum of Zoology.
  www.animaldiversity.ummz.umich.edu/site/accounts/
classification/path/Canidae.html#Canidae

-Brecht, Christy and Linzey, Don.  Gray Wolf.
  Wytheville Community College.
  www.discoverlife.org/nh/tx/Vertebrata/Mammalia/Canidae/lupus

-California Wolf Center.  www.californiawolfcenter.com

-CalPhotos.  Canis lupus; Gray Wolf.  Photo Database.
   http://calphotos.berkeley.
edu/cgi/img_query?query_src=photos_fauna
_com-Mammal&enlarge=0091+3183+0990+0121

-Chavez, Andreas S., Eric M. Gese, and Richard S. Krannich.
  "Attitudes of rural landowners toward wolves
 in northwestern Minnesota."  Wildlife Society Bulletin,
 (2005): 517-527. http://web.ebscohost.com

-Olsen, Stanley J.  "Origins of the Domestic Dog:
 The Fossil Record."  Tucson, Arizona:
 The University of Arizona Press, 1985.

-Peterson, Rolf O., Amy K. Jacobs, Thomas D. Drummer,
 L. David Mech, and Douglas W. Smith.  "Leadership behavior in relation
 to dominance and reproductive status in gray wolves, Canis lupus."
  Can.J.Zool.80:1405-1412 (2002).  http://web.ebscohost.com

-Peterson, Rolf O., James D. Woolington, and Theodore N. Bailey.  "Wolves of the Kenai Peninsula, Alaska."  Wildlife Monographs: A Publication of the Wildlife Society.  Blacksburg: The Wildlife Society, Inc., 1984.

-Van Ballenberge, Victor.  "Ecology of the Timber Wolf in Northeastern Minnesota."  Wildlife Monographs: A Publication of the Wildlife Society.  Louisville:  The Wildlife Society, Inc., 1975.