7Newton JR. Cl&s.sification and comparison of oral contraceptives containing new generation progestogens. Hum Reprod Update,1995,1 (2) :231-263.
8Wailing M. A multicenter efficacy and safety study of an oral contraceptive containing 150μg desoge.strel and 30μg ethinyl strodiol.Contraception, 1992,46 ( 2 ) : 313-326.
9Crook D, Godsland IF, Worthinton M. A comparative metabolic study of two low -estrogen-dose oral contraceptives containing desgestrel or gestodene progestin. Am J Obstet Gynecol, 1993, 169(5) : 1183-1189.
10Crosiganani PC,, Finelli F, Pizzi C. Multieenter clinical trial on triphasic gestodene. In: Genazzani AR, Skouby SO(eds). Triphasic Gestodene- a new approch to oral contraception. 1992 Parthenon Publishing,Camforth. UK,77Corson SL. Efficacy and clinical profile of a new oral contraceptive containing norgestimate. Acta Obstet Gynecol Scand Suppl, 1990,152( 1 ) :25-31.