Denadai, J., Paulillo, A. C., Schmidt , E. M. dos S., Martins, G. R. V., & Carrasco, A. de O. T. (2013). Investigation of the State of Virus Carrier of Newcastle Disease in Budgerigars (Melopsittacus undulatus). International Journal of Poultry Science, 12(3), 135–137. https://doi.org/10.3923/ijps.2013.135.137