@article{JETPL.103.657, title = {}, author = {, and Beltukov, Y. M. and , }, journal = {JETP Lett.}, volume = {103}, issue = {9}, pages = {577}, year = {2016}, doi = {}, url = {http://jetpletters.ru/ps/0/article_31797.shtml}, note = {[Pisma v ZhETF 103, 657 (2016)]} }