@article{JETPL.104.435, title = {}, author = {, and , and , and , and Kudryashov, S. I. and , and , }, journal = {JETP Lett.}, volume = {104}, issue = {6}, pages = {421}, year = {2016}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X16180119}, note = {[Pisma v ZhETF 104, 435 (2016)]} }