@article{JETPL.105.737, title = {}, author = {Tikhonov, A. M.}, journal = {JETP Lett.}, volume = {105}, issue = {12}, pages = {775}, year = {2017}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X17120062}, note = {[Pisma v ZhETF 105, 737 (2017)]} }