Jetsawangsri, T., Saropala, N., Chittachareon, A., Rangsiprakarn, R., & Herabutya, Y. (1996). A Preliminary Report on Mid-trimester Routine Ultrasonographic Screening in Ramathibodi Hospital. Thai Journal of Obstetrics and Gynaecology, 8(4), 301–305. retrieved from https://he02.tci-thaijo.org/index.php/tjog/article/view/92544