Oladele, Sunday Blessing, et al. “Survey for Serum Neuraminidase, Free and Erythrocyte Surface Sialic Acid from Chickens Vaccinated Against Newcastle Disease and the Unvaccinated Chickens Reared under Semi-Intensive Management System”. International Journal of Poultry Science, vol. 6, no. 12, Nov. 2007, pp. 933–936, https://doi.org/10.3923/ijps.2007.933.936.