., K., Kumar, D., Verma, A., Chaurasia, S. and Nag, R. (2017) “Cervical sonomorphometric evaluation of normal and preterm labour by transvaginal and transabdominal sonography”, International Journal of Reproduction, Contraception, Obstetrics and Gynecology, 6(2), pp. 417–422. doi: 10.18203/2320-1770.ijrcog20170042.