1. First findings of tubal ova in the cow, together with notes on oestrus;Hartman C.;Anat. Rec.,1931
2. Winters L. Green W. andComstock R.(1942).Prenatal development of the bovine. Technical Bulletin 151.St Paul MN:University of Minnesota Agricultural Experiment Station.
3. Development of the egg of the cow up to the stage of blastocyst formation;Hamilton W.;J. Anat.,1946
4. The influence of in vitro culture and cooling on the survival and development of cow embryos;Trounson A.;J. Reprod. Fertil.,1976