1. F. Calogero:Lett. Nuovo Cimento,20, 251, 489 (1977).
2. F. Calogero:Nuovo Cimento,43 B, 177 (1978).
3. S. Ahmed:Lett. Nuovo Cimento,22, 367 (1978).
4. S. Ahmed, M. Bruschi, F. Calogero, M. A. Olshanestky andA. M. Perelomov:Nuovo Cimento (in press).
5. Here, and always in the following, a prime appended to a sum indicates that the singular terms must be omitted; a prime appended to a function indicate differentiation.