Shubhrat Maheshwari, and Aditya Singh. “A Comprehensive Review on COVID-19 Variant: Delta Plus and Omicron Variant”. International Journal of Pharma Professional’s Research (IJPPR), Vol. 14, no. 2, 1, pp. 55-60, https://ijppronline.com/index.php/IJPPR/article/view/279.