R. A. Kohn, K. F. Kalscheur, and E. Russek-Cohen. 2002. Evaluation of Models to Estimate Urinary Nitrogen and Expected Milk Urea Nitrogen. J. Dairy Sci. 85:227–233
Article en anglès. Model per determinar el N ureic a la llet a través del N a l'orina. JDSci 2002.
R. A. Kohn, K. F. Kalscheur, and E. Russek-Cohen. 2002. Evaluation of Models to Estimate Urinary Nitrogen and Expected Milk Urea Nitrogen. J. Dairy Sci. 85:227–233