Chambers, H. “The Pathologist and Perinatal Medicine Part I - Perinatal Epidemiology - Improving the Data Set”. Thai Journal of Obstetrics and Gynaecology, vol. 6, no. 1, Jan. 1994, pp. 51-70, https://he02.tci-thaijo.org/index.php/tjog/article/view/257804.