Tavzikh Ibragimovich Ibragimov,

Kazan Federal University,

18 Kremlyovskaya Str., Kazan, 420008, Russia,

Tavzikh.Ibragimov@ksu.ru.

Ravza E'kzamovna Kulsharipova,

Kazan Federal University,

18 Kremlyovskaya Str., Kazan, 420008, Russia,

rkulshar@mail.ru.

 

Аrticle