1. Comparison of methods of estimating milk and fat production in dairy cows;Alexander;J. Dairy Sci.,1949
2. Ashton, E. D. 1948. Frequency distribution of percentage errors in milk yields calculated from 154 lactation records. [Quoted in Milk and Butterfat Recording (1956), p. 49.]
3. Ashton, E. D. 1956. Milk and Butterfat Recording. A World Survey. Tech. Commun. 3, Commonwealth Bur. of Dairy Sci. and Technol., Farnham Royal, Bucks, England.
4. A comparison of bimonthly and quarterly testing with monthly testing for estimating dairy cattle production;Bayley;J. Dairy Sci.,1952
5. The accuracy of various methods of estimating a dairy cow's production of milk and butterfat;Campbell,1946