Nishizawa, M. et al. 2006. Study of Experimental Vaccination in White Pekin Duck (Anas platyrhynchos) Against Newcastle Disease: Investigation of the State of Virus Carrier. International Journal of Poultry Science. 5, 8 (Jul. 2006), 786–788. DOI:https://doi.org/10.3923/ijps.2006.786.788.