Lin Kathleen, Coutifaris Christos
Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Clin Obstet Gynecol. 2007 Mar;50(1):268-76. doi: 10.1097/GRF.0b013e3180305fe4.