Mubila, L. F., A. M. Sailen, L. A. Mdimi, E. Barnabas, R. S. Mwakapuja, and J. J. Malago. “Effects of Vitamin A Supplementation in Local Free Range Chickens Vaccinated With Newcastle Disease Vaccine in Wami Dakawa, Morogoro, Tanzania”. Tanzania Veterinary Journal, vol. 36, no. 1, Feb. 2020, pp. 50-53, http://tvj.sua.ac.tz/vet2/index.php/TVJ/article/view/77.