Russell, William M.S. / Burch, Rex L. (1959): The Principles of Humane Experimental Technique. London: Methuen, especially pp. 69-154. Online Version

German Federal Institute for Risk Assessment (BfR) Online Version

European Union Reference Laboratory for alternatives to animal testing (EURL-ECVAM) Online Version

European Partnership for Alternative Approaches to Animal Testing (EPAA) Online Version