Srivastava, G., Mumal Nagwani, V. . Tewari, S. . Khanduri, S. Kunwar, and Prince Kapoor. “An Ultrasonographic Study to Evaluate the Correlation of Calcified Yolk Sac With Spontaneous Abortion”. Asian Journal of Medical Sciences, vol. 13, no. 4, Apr. 2022, pp. 182-6, doi:10.3126/ajms.v13i4.41499.