1. Slawny J.: On factor representations and the C*-algebra of canonical communications relations. Preprint (1971).
2. Manuceau, J.: Ann. Inst. Henri PoincaréVIII (2), 139 (1968).
3. Rocca, F., Sirugue, M., Testard, D.: Commun. math. Phys.19, 119 (1970).
4. Grossmann, A.: Private communications.
5. Naimark, M. A.: Normed rings. Groningen, The Netherlands: 1966. P. Noordhoff N. W.