1. For a treatment of Galois field theory, see,e.g.,B. Segre:Lezioni di geometria moderna, vol.1 (Bologna, 1948);L. Dickson:Linear Groups (New York, 1958).
2. G. Jarnefelt:Ann. Acad. Sci. Fennicae A.I., No. 96 (1951);
3. P. Kustaanheimo Publ. Astron. Obs. Helsinki, No.32 (1959);
4. No. 52 (1957),Rend. Mat.,16, 286 (1967)). For more widely available accounts of the problem see also ref. (3–5).H. R. Coish:Phys. Rev. 114, 383 (1959).I. S. Shapiro:Nucl. Phys. 21, 474 (1960).H. Joos:Journ. Math. Phys.,5, 155 (1964);
5. H. R. Coish:Phys. Rev.,114, 383 (1959).