Dr. N. Sriram, Dr. S. Kameshwaran, and Ebenezer David. 2021. “Worldwide Covid-19 Approved Vaccines - A Comprehensive Review on Corona Virus Vaccines”. International Journal of Allied Medical Sciences and Clinical Research 9 (2):207-12. https://doi.org/10.61096/ijamscr.v9.iss2.2021.207-212.