1. H. Lehmann:Nuovo Cimento,11, 342 (1954).
2. For the Lagrangian formulation of renormalizable theories see (2).
3. K. Symanzik:Greens Functions etc., Hercegnovi Lectures.
4. H. P. Dürr, W. Heisenberg, H. Mitter, S. Schlieder andK. Yamazaki:Zeits. f. Naturf.,14a, 441 (1959).
5. H. P. Dürr:Zeits. f. Naturf.,16 A, 327 (1961).