Infertile couples with normal counts who require subzonal sperm insertion possess a fertility defect that affects zona pellucida penetration
Lih CH, Grunfeld L, Sandler B, Drews MR, Navot D, Gordon JW.
Infertile couples with normal counts who require subzonal sperm insertion possess a fertility defect that affects zona pellucida penetration.
Hum Reprod 1994; 9:2335-8.