Thanks go to:

Melissa Kaplan, http://www.anapsid.org/box.html

Tess Cook, http://www.boxturtlesite.org/

Carroll, David M. The Year of the Turtle: A Natural History. 1991. Camden House publishing.

De Vosjoli, Philippe. The General Care and Maintenance of Red-Eared Sliders. 1992. Advanced Vivarium Systems, Inc.

Obst, Fritz, et al. The Completely Illustrated Atlas of Reptiles and Amphibians for the Terrarium. 1988. TFH Publishing, Inc.

Pritchard, Peter C. H. Encyclopedia of Turtles. 1979. TFH Publishing.

Schwartz, C. W. and E. R. 1974. The Three-toed Box Turtle in Central Missouri: Its Population, Home Range, and Movements.
Schwartz, E. R., C. W., and A. R. Kiester. 1984. The Three-toed Box Turtle in Central Missouri, Part II: A Nineteen-year Study of Home Range, Movements and Population.

Alderton, D.: Turtles and Tortoises of the World. New York, New York: Facts on File, 1988.
Ernst, C.H. and Barbour, R.W.: Turtles of the World. Washington D.C.: Smithsonian Institution Press, 1989.
Highfield, A.C.: Keeping and Breeding Tortoises in Captivity. Avon, England: R & A Publishing, 1990.
Obst, F.J.: Turtles, Tortoises and Terrapins. St. Martin's Press, New York, 1988.
Pritchard, P.C.H.: Encyclopedia of Turtles. Neptune City, New Jersey: T.F.H. Publications. 1979.
Pursall, B.: Mediterranean Tortoises. Neptune City, New Jersey: T.F.H. Publications, 1994.
Wahlquist, H.: Horsfield's tortoise, Agrionemys horsfieldii. Tortuga Gazette 27(6): 1-3, June 1991.