Izugbara, Chibuogwu. “Spousal Age Differences and Risk of Infant Mortality in Nigeria: A Multi-Level Analysis”. The Columbia University Journal of Global Health 5, no. 1 (May 15, 2015): 3–6. Accessed January 24, 2022. https://journals.library.columbia.edu/index.php/jgh/article/view/5293.