Энгельс
SerebryakovA.V.Engels Technological Institute (affiliated branch) of Saratov State Technical University, 17, Svoboda Square, Engels, Saratov region, 413100, Russiabundzin@inbox.ru
El’kinMikhailDavidovichEngels Technological Institute (affiliated branch) of Saratov State Technical University, 17, Svoboda Square, Engels, Saratov region, 413100, Russiaelkinmd@mail.ru
El’kinPavelMikhailovichEngels Technological Institute (affiliated branch) of Saratov State Technical University, 17, Svoboda Square, Engels, Saratov region, 413100, Russiapashaelkin@yandex.ru