Mukdee, Cattleya, Thitima Suntharasaj, and Chusana Petpichetchian. “Prediction of Successful Normal Vaginal Delivery by Ultrasonographic Measurement of Occiput-spine Angle during First Stage of Labor”. Thai Journal of Obstetrics and Gynaecology 29, no. 5 (September 1, 2021): 288–297. accessed September 25, 2026. https://he02.tci-thaijo.org/index.php/tjog/article/view/185794.