1. E. Goursat:Cours d’analyse mathematique, Tome II, edited by Gauthier-Villars (Paris, 1949), p. 441;J. Ames andD. Murnaghan:Theoretical Mechanics (New York, N. Y., 1959), p. 346;R. Hermann:Differential Geometry and the Calculus of Variations, Part I (New York, N. Y., 1968).
2. R. Hermann:Differential Geometry and the Calculus of Variations, Parti (New York.N. Y., 1968), p. 42.
3. A. Kumar:Phys. Rev. D,8, 1028 (1973).
4. M. Andrie andD. Simms:Journ. Math. Phys.,13, 331 (1972).
5. C. Palmieri andB. Vitale:Nuovo Cimento,66 A, 299 (1970) and the detailed bibliography given there on the direct and inverse Noether’s theorem in classical point dynamics.