Okwor, E.C., and D.C. Eze. “Outbreak and Persistence of Mareks Disease in Batches of Birds Reared in a Poultry Farm Located in Nsukka, South East Nigeria”. International Journal of Poultry Science, vol. 10, no. 8, July 2011, pp. 617–620, https://doi.org/10.3923/ijps.2011.617.620.