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2. Sex Ratios of Fetal Calves;Chapman;Proc. Am. Soc. Animal Production,1938
3. Cystic Ovaries and Twinning in Holsteins;Clapp;Cornell Vet.,1934
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5. Erb, R. E., Anderson, W. R., Hinze, P. M., and Gildow, E. M. Inheritance of Twinning in a Herd of Holstein-Friesian Cattle. Unpublished results. Washington Agr. Expt. Sta. 1959.