1. A. M. Kagan, Yu. V. Linnik, and C. R. Rao, Characterization Problems of Mathematical Statistics [in Russian], Nauka, Moscow (1972).
2. E. Lukacs and R. G. Laha, Applications of Characteristic Functions, Hafner, London (1964).
3. E. Lukacs, Stochastic Convergence, Second Edition, Academic Press, London-New York (1975).
4. H. Cramer, Random Variables and Probability Distributions, Cambridge Univ. Press, London-New York (1937).
5. N. A. Sapogov, ?Stability problem for Cramer's theorem,? Izv. Akad. Nauk SSSR, Ser. Mat.,15, No. 3, 205?218 (1951).