@article{JETPL.109.61, title = {}, author = {Bobkova, I. V. and Bobkov, A. M.}, journal = {JETP Lett.}, volume = {109}, issue = {1}, pages = {57}, year = {2019}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.1134/S0370274X19010119}, note = {[Pisma v ZhETF 109, 61 (2019)]} }