@article{JETPL.108.657, title = {}, author = {Nekrasov, I. A. and Pavlov, N. S.}, journal = {JETP Lett.}, volume = {108}, issue = {9}, pages = {623}, year = {2018}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.1134/S0370274X18210105}, note = {[Pisma v ZhETF 108, 657 (2018)]} }