@article{JETPL.106.549, title = {}, author = {Kovalev, V. M. and , }, journal = {JETP Lett.}, volume = {106}, issue = {9}, pages = {565}, year = {2017}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X17210032}, note = {[Pisma v ZhETF 106, 549 (2017)]} }