C. Okonkwo, F. . Iwuamadi, M. Sanda, and A. . Igwe, “Vaccination indices and concomitant serological status of Newcastle disease in chickens in Aba and Umuahia of Abia State”, Sokoto J. Vet. Sc., vol. 20, no. 1, pp. 35–41, May 2022.