1. The cervix and its mucus;Elstein;Clin Obstet Gynaecol,1974
2. Correlation between cervical penetration and seminal tests;Lübke,1967
3. Diagnosis and classification of the cervical factor of infertility;Insler,1977
4. Immunological factors and the post-coital test in unexplained infertility;Soffer;Int J Fertil,1975
5. Artificial insemination—donor and husband;Matthews,1980