Chandran, Priya, M. P. Lilabi, Thomas Bina, Jayakrishnan Thavody, and Smiji George. “Re-Emergence of Diphtheria in Kerala: The Need for Change in Vaccination Policy”. International Journal Of Community Medicine And Public Health 6, no. 2 (January 24, 2019): 829–835. Accessed October 27, 2025. https://www.ijcmph.com/index.php/ijcmph/article/view/4168.