@article{JETPL.108.670, title = {}, author = {, and , and , and Trakhtenberg, L. I.}, journal = {JETP Lett.}, volume = {108}, issue = {9}, pages = {637}, year = {2018}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.1134/S0370274X18210130}, note = {[Pisma v ZhETF 108, 670 (2018)]} }