1. R. Feynman, “The principle of least action in quantum mechanics,” Doctoral dissertation No. 12-03, Princeton Univ., Princeton, N. J. (1942).
2. V. P. Maslov, Operator Methods [in Russian], Nauka, Moscow (1973); English transl.: Operational Methods, Mir, Moscow (1976).
3. L. D. Landau and E. M. Lifshits, Theoretical Physics [in Russian], Vol. 3, Quantum Mechanics: Non-Relativistic Theory, Fizmatlit, Moscow (1963); English transl., Pergamon, London (1965).
4. V. P. Maslov, Math. Notes, 85, 613–622 (2009).
5. S. Gindikin, Histoires de mathématiciens et de physiciens [in Russian], MTsIMO, Moscow (2001); French transl., Cassini, Le Set et le Fer, Paris (2000).