Schwartz J, Van de Pavert S, Clarke I, Rao A, Ray D, Vrana K
Department of Obstetrics & Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
Ann N Y Acad Sci. 1998 May 15;839:239-43. doi: 10.1111/j.1749-6632.1998.tb10767.x.