1. Alexander, D. J.: Comparison of the structural polypeptides of four avian paramyxoviruses. Arch. ges. Virusforsch.46, 291–301 (1974).
2. Almeida, J. D., Berry, D. M., Cunningham, C. H., Hamre, D., Hofstad, M. S., Mallucci, L., McIntosh, K., Tyrrell, D. A. J.: Coronaviruses. Nature (Lond.)220, 650 (1968).
3. Apostolov, K., Flewett, T. H., Kendal, A. P.: In:Barry, R. D., Mahy, B. W. J. (eds.), The biology of large RNA viruses, 3–26. London-New York: Academic Press 1970.
4. Akers, T. G., Cunningham, C. H.: Replication and Cytopathogenicity of avian infectious bronchitis virus in chick embryo kidney cells. Arch. ges. Virusforsch.25, 30–37 (1968).
5. Becker, W. B., McIntosh, K., Dees, J. H., Chanock, R. M.: Morphogenesis of avian infectious bronchitis virus and a related human virus (strain 229E). J. Virol.1, 1019–1027 (1967).