Tanmoun N, Raungrongmorakot K, Ruangvutilert P, Boriboonhirunsarn D, Tontisirin P, Butsansee W. Correlation of Cervical Length Obtained from Transperineal Ultrasonography, Transvaginal Ultrasonography and Digital Examination. Thai J Obstet Gynaecol [internet]. 2017 Apr. 19 [cited 2026 Sep. 28];15(3):137-44. available from: https://he02.tci-thaijo.org/index.php/tjog/article/view/83341