Limpanyalert, P., and S. Manotaya. “Standard Curve of Symphysial-Fundal Height Measurement and Pregnancy Characteristics in Pregnant Women at King Chulalongkorn Memorial Hospital”. Thai Journal of Obstetrics and Gynaecology, vol. 13, no. 4, Oct. 2001, pp. 197-06, https://he02.tci-thaijo.org/index.php/tjog/article/view/256647.