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2. R. Casalbuoni:Nuovo Cimento,33 A, 115 (1976).
3. R. Casalbuoni:Nuovo Cimento,33 A, 389 (1976).
4. Yu. A. Gel’fand andE. P. Likhtman:JETP Lett.,13, 323 (1971);D. V. Volkov andV. P. Akulov:Phys. Lett.,46 B, 109 (1973);J. Wess andB. Zumino,Nucl. Phys.,70 B, 39 (1974);A. Salam andJ. Strathdee,Nucl. Phys.,76 B, 477 (1974). See alsoB. Zumino:Proc. of the VII International Conference on High-Energy Physics (London, 1974), Rutherford Laboratory, Chilton, Didcot (1974), pp. I-254. A great impact in the development of the supersymmetries has been given by the dual models, seeA. Neveu andJ. H. Schwarz:Nucl. Phys.,31 B, 86 (1971);P. Ramond:Phys. Rev. D,3, 2415 (1971).
5. SeeD. V. Volkov andV. P. Akulov (4), see alsoA. Salam andJ. Strathdee:Phys. Rev. D,11, 1521 (1975). For more recent attempts along this line, seeL. N. Chang, K. I. Macrae andF. Mansouri:Phys. Rev. D,13, 235 (1976);Y. M. Cho andP. G. O. Freund:Phys. Rev. D,12, 1711 (1975);P. Nath andR. Arnowitt:Phys. Lett.,56 B, 171 (1975);B. Zumino:Supersymmetry, CERN preprint TH 2120, 1976.