Pinnington, T. R., J. Arthan, C. Komoltri, and P. Chanprapaph. “Accuracy of the Combined First Trimester Down Syndrome Screening Test and the Optimum Range of the Cut-off Point for Intermediate-risk Identification: Twelve years’ experience”. Thai Journal of Obstetrics and Gynaecology, vol. 32, no. 4, July 2024, pp. 269-77, https://he02.tci-thaijo.org/index.php/tjog/article/view/264887.