Essig, Maria G.; Edited by Susan Van Houten and Tracy Landauer, Reviewed by Martin Gabica and Avery L. Seifert. Semen Analysis. Healthwise. WebMD. 2007-02-20 [2007-08-05]. (原始内容存档于2007-10-15).
Essig, Maria G.; Edited by Susan Van Houten and Tracy Landauer, Reviewed by Martin Gabica and Avery L. Seifert. Semen Analysis. Healthwise. WebMD. 2007-02-20 [2007-08-05]. (原始内容存档于2007-10-15).