@article{JETPL.104.637, title = {}, author = {, and , and , and Averkiev, N. S.}, journal = {JETP Lett.}, volume = {104}, issue = {9}, pages = {615}, year = {2016}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X16210050}, note = {[Pisma v ZhETF 104, 637 (2016)]} }