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2. V. I. Gol'danskii et al., Statistics of Counts in Registration of Nuclear Particles [in Russian], Moscow (1959).
3. I. M. Verkhovskii, Principles of Design and Evaluation of Beneficiation Processes of Minerals [in Russian], Ugletekhizdat, Moscow (1949).
4. A. G. Vasil'ev and K. S. Klempner, Radioisotope Relays [in Russian], Mashinostroenie, Moscow (1971).