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3. V. F. Zheverzheev, L. A. Kal’nitskii, and N. A. Sapogov, Special Course of Higher Mathematics for Technical Universities [in Russian], Vysshaya Shkola, Moscow (1970).
4. B. Ya. Levin, Distribution of Zeros of Entire Functions [in Russian], Gostekhteoretizdat, Moscow (1956).
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