1. Lalan, V.: Bull. Soc. Math. France65, 83 (1937).
2. Bacry, H., Lévy-Leblond, J.-M.: J. Math. Phys.9, 1605 (1968).
3. Gorini, V.: Derivation of the Lorentz and Galilei groups from rotational invariance. Seminar delivered at the International Advanced Study Institute on Mathematical Physics, Robert College, Istanbul, Turkey, August 10–21, 1970. To appear in the proceedings.
4. Berzi, V., Gorini, V.: Space-time, reference frames, relativistic invariance: a topological approach. Milan University report IFUM 108/FT-1970. Unpublished.
5. Gantmacher, F.R.: The theory of matrices, Vol. 1, Chapter IX, p. 285. New York: Chelsea Publ. Comp. 1959.