Tkachev, ︠. A., & ︠I︡Udovich, ︠. Ė. (1975). Statisticheska︠i︡a obrabotka geokhimicheskikh dannykh: Metody i problemy. Nauka, Leningradskoe otd-nie.
Lua i Stíl Chicago (17ú heag.)Tkachev, ︠I︡U. A., agus ︠I︡Akov Ėlʹevich ︠I︡Udovich. Statisticheska︠i︡a Obrabotka Geokhimicheskikh Dannykh: Metody I Problemy. Leningrad: Nauka, Leningradskoe otd-nie, 1975.
Lua MLA (8ú heag.)Tkachev, ︠I︡U. A., agus ︠I︡Akov Ėlʹevich ︠I︡Udovich. Statisticheska︠i︡a Obrabotka Geokhimicheskikh Dannykh: Metody I Problemy. Nauka, Leningradskoe otd-nie, 1975.
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