Reddy, I.J., et al. “Active Immunization Against CVIP and It`s Role on the Pattern of Sequence Length and Pause Days in Domestic Hen (Gallous Domesticus)”. International Journal of Poultry Science, vol. 5, no. 2, Jan. 2006, pp. 156–161, https://doi.org/10.3923/ijps.2006.156.161.