Pornprasertsuk, W., C. Treetampinich, N. Israngura Na Ayudhya, P. O-Prasertsawat, and S. Rattanasiri. “Relationship between Alteration of Sacral Pain and Cervical Progression in Latent Phase of Labor : Diagnostic Study”. Thai Journal of Obstetrics and Gynaecology, vol. 16, no. 2, Apr. 2017, pp. 97-102, https://he02.tci-thaijo.org/index.php/tjog/article/view/82275.