1. Cohen, J., Alikani, M., Trowbridge, J. et al. (1992) Implantation enhancement by selective assisted hatching using zona drilling of human embryos with poor prognosis. Hum. Reprod.,7,685–691.
2. Cummins, J.M. and Breen, T.M. (1986) Embryo gradings. J. In vitro Fert. Embryo. Transf.,5,284–295.
3. Dirnfeld, M., Goldman, S., Koifman, M. et al. (1993) Very short exposure of oocytes to normal sperm in vitro improves implantation rates: a prospective randomized study (Abstract 0–154) In Proceedings of the 51st Annual Meeting of the American Society for Reproductive Medicine, 1995, American Society for Reproductive Medicine, Seattle, S76.
4. Dumoulin, J.C.M., Bras, M., Land, J.A. et al. (1992) Effect of the number of inseminated spermatozoa on subsequent human and mouse embryonic development in vitro. Hum. Reprod.,7,1010–1013.
5. Free, D.A., Merryman, D.C., Stringfellow, S.E. et al. (1998) Limited oocyte-sperm co-incubation time does not improve embryo quality, implantation, or pregnancy rate in patients undergoing in vitro fertilization. Abstract 0–263, IFFS `98, 16th World Congress on Fertility and Sterility, and 54th Annual Meeting of the American Society for Reproductive Medicine. Fertil. Steril. (Suppl.), 70, S98–S99.