1. Utilization of urea by;Balch;The Journal of Dairy Research, Vol.,1961
2. Conway , E. J. 1950 Microdiffusion analysis and volumetric error. 3. Aufl.
3. Influence of dietary nitrogen on nitrogen metabolism in;Davis;J. Dairy Sci.,1964
4. Farries , E. F. 1967 Persönliche Mitteilung