Wegbom, A. I., I. D. Essi, and V. A. Kiri. “Estimation of the Family and Community Unobserved Heterogeneity Effects on the Risk of Under-Five Mortality in Nigeria Using Frailty Model”. International Journal of Child Health and Nutrition, vol. 9, no. 1, Mar. 2020, pp. 17-25, doi:10.6000/1929-4247.2020.09.01.3.