1. Hogan, B. et al. in Manipulating the Mouse Embryo, A Laboratory Manual 2nd edn. (eds. Hogan, B., Beddington, H., Constantini, F. & Lacy, C.) Section C 127–188 (Cold Spring Harbor Press, Plainview, NY, 1994).
2. United States Department of Agriculture. Animal Welfare Act and Animal Welfare Regulations (USDA, Beltsville, MD, 1992).
3. Institute of Laboratory Animal Resources, National Research Council. Guide for the Care and Use of Laboratory Animals 64 (National Academy Press, Washington, DC, 1996).
4. Danneman, P.J. in Anesthesia and Analgesia in Laboratory Animals (eds. Kohn, D.F., Wixson, S.K., White W.J. & Benson, G.J.) ch. 6 83–103 (Academic, San Diego, 1997).
5. United States Department of Agriculture. Animal Care Policy Manual policy #11 (USDA, Beltsville, MD 1997).