1. I. M. Gel'fand, D. A. Raikov, and G. E. Shilov, Commutative Normed Rings [in Russian], Fizmatgiz, Moscow (1960).
2. S. A. Antonyan, Dokl. Akad. Nauk ArmSSR,69, No. 5, 260?264 (1979).
3. J. De Vries, "Topological transformation groups. I," Amsterdam (1975).