Tongsong, T., C. Wanapirak, and W. Piyamongkol. “Prenatal Sonographic Diagnosis of Cystic Hygroma Colli”. Thai Journal of Obstetrics and Gynaecology, vol. 8, no. 3, July 1996, pp. 189-95, https://he02.tci-thaijo.org/index.php/tjog/article/view/257606.