1. Schlieder, S., Seiler, E.: Commun. math. Phys.31, 137 (1973)
2. Streater, R., Wightman, A.: PCT, spin, and statistics and all that. New York: Benjamin 1964;
3. Jost, R.: The geneal theory of quantized fields, AMS, Providence 1965
4. Hall, D., Wightman, A.: Mat. Phys. Medd. Dan. Vid. Selsk.35, No. 5 (1957)
5. DeMottoni, P., Genz, H.: Nuovo Cimento67 B, 1 (1970)