Izhevsk ErokhinaLiudmila N. Udmurt State University, Russia, 426034, Izhevsk, Universitetskaya street, 1 erochin@yandex.ru Read more about Erokhina Liudmila N. Erokhin Aleksander V. Izhevsk State Technical University, 7 Studencheskaya St., Izhevsk 426069, Russia erochin@yandex.ru Read more about Erokhin Aleksander V. KamitovaAlevtinaVasilyevna Udmurt Institute of History, Language, and Literature, Ural Branch of the Russian Academy of Science, 426004, Russia, Izhevsk, Lomonosova st., 4 akamitova@mail.ru Read more about Kamitova Alevtina Vasilyevna DubovtsevAlekseiNikolayevich Udmurt State University, Russia, 426034, Izhevsk, Universitetskaya street, 1 dubovcev-aleksei@mail.ru Read more about Dubovtsev Aleksei Nikolayevich