B. Affandi, S. K. Suherman, T. Korver, T. Paul Geurts, and H. Coelingh Bennink, “A pharmacokinetic and pharmacodynamic study with a single implant containing 3-ketodesogestrel (Implanon®)”, Med J Indones, vol. 8, no. 1, pp. 15-24, Jan. 1999.