Adeleke, K.A., and A.A. Abiodun. “An Alternative Stratified Cox Model for Correlated Variables in Infant Mortality”. International Journal of Statistics in Medical Research 8 (July 8, 2019): 23–31. Accessed May 2, 2025. https://www.lifescienceglobalca.com/index.php/ijsmr/article/view/6006.