@article{JETPL.107.449, title = {}, author = {, and , and Proshin, Yu. N.}, journal = {JETP Lett.}, volume = {107}, issue = {7}, pages = {426}, year = {2018}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X18070081}, note = {[Pisma v ZhETF 107, 449 (2018)]} }