1. Estimates of sire-son relationships for yield traits in the five major dairy breeds;Dickinson;J. Dairy Sci.,1969
2. Yield adjustments for differences in age at calving;Hickman;Acta Agr. Scand.,1968
3. Kendrick, J. F. 1955. Standardizing dairy herd-improvement-association records in proving sires. ARS-52-1, USDA.
4. Bulls with high PD sire better cattle;McDaniel;Hoard's Dairyman,1968
5. Environmental influences on age correction factors;McDaniel;J. Dairy Sci.,1966