1. Dickinson, F. N., H. D. Norman, R. L. Powell, L. G. Waite, and B. T. McDaniel. 1976. Procedures used to calculate the USDA-DHIA Modified Contemporary Comparison. Page 18 in USD A Prod. Res. Rep. 165.
2. Information on proving sires in Dairy Herd-Improvement Associations;Kendrick;USDA Cir. BD1M,1933
3. The comparative performance of registered and identified grade cows for milk and fat yield;Kennedy;Can. J. Anim. Sci.,1978
4. New Zealand Dairy Board, Farm Production Division. 1980. 56th Farm Production Report, 1979–80 Season. Pastoral House, Lambton Quay, Wellington, New Zealand.
5. Norman, H. D., and F. N. Dickinson. 1971. An economic index for determining the relative value of milk and fat in Predicted Differences of bulls and Cow Index values of cows. USDA, ARS-44-223, Dairy Herd Improvement Letter 47(1).