@article{JETPL.105.616, title = {}, author = {Dolganov, P. V.}, journal = {JETP Lett.}, volume = {105}, issue = {10}, pages = {657}, year = {2017}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X17100071}, note = {[Pisma v ZhETF 105, 616 (2017)]} }