@article{JETPL.108.541, title = {}, author = {Zakharov, B. G.}, journal = {JETP Lett.}, volume = {108}, issue = {8}, pages = {508}, year = {2018}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.1134/S0370274X18200031}, note = {[Pisma v ZhETF 108, 541 (2018)]} }