Wild Mammals in Captivity: Principles and Techniques by Devra G. Kleiman, Mary E. Allen, Katerina V. Thompson, and Susan Lumpkin (1997)
Second Nature: Environmental Enrichment for Captive Animals by David J. Shepherdson, Jill D. Mellen, and Michael Hutchins (1998)
The Biology of Animal Stress: Basic Principles and Implications for Animal Welfare (Cabi Publishing) by G. P. Moberg and J. A. Mench (2000)
Environmental Enrichment for Captive Animals (UFAW Animal Welfare) by Robert J. Young (2003)
Animal Welfare: Limping Towards Eden (UFAW Animal Welfare) by John Webster (2005)
Domestic Animal Behaviour and Welfare by D.M. Broom and A.F. Fraser (2007)
Zoos and Animal Welfare (Issues That Concern You) by Christine Van Tuyl (2007)