1. Albright, J. L. (1992) Purdue University's animal welfare and teaching programs.Proceedings of the Livestock Conservation Institute Annual Meeting, USA, p. 106.
2. Baker, F. H. (Ed.). (1981). Scientific aspects of the welfare offood animals. (Rep. No. 91).Arnes, Iowa: Council for Agricultural Science Technology.
3. Baumgardt, B. R. & Gray, H. G. (Eds.). (1993). Food animal well-being conferenceproceedings and deliberations.West Lafayette, IN: U.S. Department of Agriculture and Purdue University Office of Agricultural Research Programs.
4. Brambell, F. W. R. (1965). Report of the technical committee to enquire into the welfare of animals kept under intensive livestock husbandry systems. (Command Rep. No. 2836).London: Her Majesty's Stationary Office.
5. Coats, C. D. (1989). Old MacDonald's factory farm.New York: Continuum.