1. Neumann, J. v.: Collected Works III. On infinite direct products. New York: Pergamon 1961.
2. Bures, D. J. C.: Compositio Math.32, 169 (1964).
3. Neumann, J. v.: Collected Works III. On rings of operators III. New York: Pergamon 1961.
4. Jelinek, F.: Thesis, Vienna (1968).
5. Trotter, H. F.: Pacific J. Math.8, 887 (1958).