Virutamasen, Pramuan, Damrong Reinprayoon, Kamthorn Pruksananonda, Rachanee Wongvathanavikrom, and Rosalin Kriengsinyos. 1989. “Clinical and Metabolic Study of a New Monophasic Formulation Containing Ethinylestradiol and Gestodene”. Thai Journal of Obstetrics and Gynaecology 1 (2). Bangkok, Thailand:81-89. https://he02.tci-thaijo.org/index.php/tjog/article/view/257901.