1. Effect of pregnancy on the live weight of dairy cows;Bartlett;J. Agr. Sci.,1926
2. Headley, F. B. 1944. Factors affecting the production of dairy cows. NV Agr. Exp. Sta., Tech. Bull. 172.
3. Matthews, C. A., and M. H. Fohrman. 1954. Beltsville growth standards for Holstein cattle. USDA, Tech. Bull. 1099.
4. Weight changes in lactating Holstein cows;Miller;J. Dairy Sci.,1969
5. Morgan, R. F., and H. P. Davis. 1936. The effect of pregnancy and parturition on the weight of dairy cows. NE Agr. Exp. Sta., Res. Bull. 82.