O. Adejinmi, C. Okpeze, O. Obi, A. Omole, A. Kehinde, and O. Awe, “The use of chicken egg shell as an alternative source of calcium in the diet of cockerel chickens”., J. Ag. For. Soc. Sci., vol. 8, no. 2, pp. 2–7, Nov. 2011.