3Sivin I.International experience with Norplant and Norplant -2 Contraceptives.Studies in family planning,1988,19:81 -94.
4Hickey M,Dwarte D,Fraser IS.Superficial endometrial vascular fragility in Norplant users and in women with ovulatory dysfunctional uterine bleeding.Hum Reprod,2000,15:1509 - 1514.
5Marsh MM,Butt AR,Riley SC,et al.Immunolocalization of endothelin and neutral endopeptidase in the endometrium of users of subdermally implanted levonorgestrel (Norplant).Hum Reprod,1995,10:2584 -2589.
6Pekonen F,Nyman T,Rutanen EM.Differential expression of mRNAs for endothelin -related proteins in human endometrium,myometrium and leiomyoma.Mole Cell Endocrinol,1994,103:165.