1. McFerran, J.B. and McCracken, R.M. In: Newcastle Disease, (Ed Alexander, D.J.) Martinus Nijhoff, Boston, 1988.
2. Beard, C.W. In: Newcastle Disease. (Ed Alexander, D.J.) Martinus Nijhoff, Boston, 1988.
3. Alexander, D.J. In: Newcastle Disease. (Ed Alexander, D.J.) Martinus Nijhoff, Boston, 1988.
4. Beard, C.W. and Hanson, R.P. In: Diseases of Poultry (Ed Hofstad, M.S.) Iowa State University Press, Ames, 1981.
5. Estola, T., Makela, P. and Hovi, T. J. Hyg. Camb. 83: 59–67, 1979.