1. V. P. Maslov, Operator Methods [in Russian], Nauka, Moscow (1973); English transl.: Operational Methods, Mir, Moscow (1976).
2. V. P. Maslov, Complex WKB Method in Nonlinear Equations [in Russian], Nauka, Moscow (1977); English transl.: Complex WKB Method for Nonlinear Equations: I. Linear Theory, Birkhauser, Basel (1994).
3. V. P. Maslov, Theorie des perturbations et methodes asymptotiques [in Russian], MSU, Moscow (1965); French transl., Dunod, Paris (1972).
4. V. G. Bagrov, V. V. Belov, and I. M. Ternov, Theor. Math. Phys., 50, 256 (1982).
5. V. P. Maslov and O. Yu. Shvedov, Complex Germ Method in the Many-Body Problem and in Quantum Field Theory [in Russian], URSS, Moscow (2000).