K E Gregory, S E Echternkamp, G E Dickerson, L V Cundiff, R M Koch, L D Van Vleck,
Twinning in cattle: I. Foundation animals and genetic and environmental effects on twinning rate. Journal of Animal Science. ,vol. 68, pp. 1867- 1876 ,(1990) ,
10.2527/1990.6871867X