1. Schulze, I. T. in The Influenza Viruses and Influenza (ed. Kilbourne, E. D.) 53–82 (Academic, London, 1975).
2. Bucher, D. & Palese, P. in The Influenza Viruses and Influenza (ed. Kilbourne, E. D.) 83–123 (Academic, London, 1975).
3. Gottschalk, A. Biochim. biophys. Acta 23, 645–646 (1957).
4. Palese, P. et al. Virology 61, 397–410 (1974).
5. Klenk, H.-D. et al. Virology 68, 426–439 (1975).