1. 1. Urasawa, S. (1975) : Virus, 25, 213-219 (text in Japanese) .
2. 2. Ackermann, W. W. and Dinka, M. (1965) : Acta Virol., 9, 526-533.
3. 3. Pagano, J. S., Gilden, R. V. and Sedwick, W. D. (1965) : J. Immunol., 95, 909-917.
4. 4. Svehag, Sven-Eric (1964) : J. Exptl. Med., 119, 517-535.
5. 5. Thomssen, R., Koehne-Barleben, G. and Schober, A. (1966) : Arch. ges. Virusforsch., 19, 415-434.