Chakarvarty N, Srivastav K, Khanduri S. A study to evaluate a correlation between various Gray Scale parameters and period of gestation. Int J Reprod Contracept Obstet Gynecol [Internet]. 2018 May 26 [cited 2025 Oct. 14];7(6):2434-40. Available from: https://www.ijrcog.org/index.php/ijrcog/article/view/4844