@article{JETPL.106.434, title = {}, author = {Gusev, A. I. and Sadovnikov, S. I.}, journal = {JETP Lett.}, volume = {106}, issue = {7}, pages = {454}, year = {2017}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X17190079}, note = {[Pisma v ZhETF 106, 434 (2017)]} }