1. Norplant System (Lev-onorgestrel Implants): Prescribing Information;United States Food Drug Administration (USFDA),1990
2. Norplant® contraceptive subdermal implants: managerial and technical guidelines;World Health Organization (WHO),1990
3. The ‘pop-out’ method of Norplant® removal. Advances in Contraception;Darney,1992
4. Sustained-release contraceptives;Darney
5. Norplant® guidelines for family planning service programs,1993