P. Dahiya, S. Jain, N. Gupta, J. sen, and N. Jain, “Comparative study of transperineal and transvaginal sonography for localization of placenta in antepartum haermorrhage”, Int J Reprod Contracept Obstet Gynecol, vol. 5, no. 1, pp. 48–52, Dec. 2016.