Kumar, D., N. Kapoor, P. R. Raghav, and M. S. Gehlot. “VDPV and Polio End Game Strategy: The Final Frontier”. International Journal of Contemporary Pediatrics, vol. 1, no. 2, Feb. 2017, pp. 128-30, https://www.ijpediatrics.com/index.php/ijcp/article/view/596.