Suntharasaj, T., O. Kor-anantakul, and R. Rattanaprueksachart. “Fetal Heart Rate Accelerations at Gestational Age 28-41 Weeks”. Thai Journal of Obstetrics and Gynaecology, vol. 9, no. 1, Mar. 1997, pp. 13-18, https://he02.tci-thaijo.org/index.php/tjog/article/view/257303.