@article{JETPL.104.512, title = {}, author = {Val?kov, V. V. and , }, journal = {JETP Lett.}, volume = {104}, issue = {7}, pages = {483}, year = {2016}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X16190085}, note = {[Pisma v ZhETF 104, 512 (2016)]} }