1. R. J. Aitken, F. Best, E. Rudak, D. Richard, O. Djahanbahkch, D. Mortimer, A. Templeton, and M. Lees (1981 ) Analysis of the fertilizing capacity of human spermatozoa . Society for the Study of Fertility, Edinburgh, Abstract 12, p.16 .
2. Human Sperm Penetration into Zona-Free Hamster Oocytes as a Test to Evaluate the Sperm Fertilizing Ability
3. J. D. Biggers, W. K. Whitten, D. G. Whittingham, and J. C. Daniel (1971 ) Methods in Mammalian Embryology (Freeman, San Francisco, p.86 .
4. Relationship between semen quality and human sperm penetration of zona-free hamster ova