Masood, A. ., S. . Dwivedi, G. . Singh, M. A. . Hassan, and A. . Singh. “Assessment Of Immunization Status of Children Between 12-23 Months in Allahabad District”. National Journal of Community Medicine, vol. 2, no. 03, Dec. 2011, pp. 346-8, https://njcmindia.com/index.php/file/article/view/1919.