%0 Journal Article %T Fertilization and early embryology: A retrospective analysis of unfertilized and presumed parthenogenetically activated human oocytes demonstrates a high frequency of sperm penetration %A Blerkom, Jonathan, Van %A Davis, Patrick, W. %A Merriam,, John %J Human Reproduction %V 9 %N 12 %P 2381-2388 %@ 0268-1161 %D 1994-12-01 %I Oxford University Press %~ DeepDyve