Orenburg GavrishI.A.Orenburg State University, 3 Pobedy Prospect, Orenburg 460018 Russiagavrish.irina.ogu@gmail.com Read more about Gavrish I. A. SizovaE.A.Orenburg State University, 3 Pobedy Prospect, Orenburg 460018 RussiaSizova.L78@yandex.ru Read more about Sizova E. A. LebedevS.V.Orenburg State University, 3 Pobedy Prospect, Orenburg 460018 Russialsv74@list.ru Read more about Lebedev