1. D. Blackwell and M. A. Girshick, Theory of Games and Statistical Decisions [Russian translation], IL, 1958.
2. A. Wald, Statistical Decision Functions, New York, 1950.
3. A. Wald, Sequential Analysis [Russian translation], Fizmatgiz, Moscow, 1960.
4. A. N. Kolmogorov, Unbiased Estimates [in Russian], Izv. AN SSSR, 14, 1950.
5. E. B. Dynkin, ?Necessary and sufficient statistics,? UMN, 6, 1, 1953.