Pengsaa, P., B. Udomthavornsuk, V. Titapan, and V. Vatanasapt. “The Epidemiology of Ovarian Cancer in Khon Kaen 1985-1989”. Thai Journal of Obstetrics and Gynaecology, vol. 2, no. 2, July 1990, pp. 95-101, https://he02.tci-thaijo.org/index.php/tjog/article/view/257889.