@article{JETPL.109.65, title = {}, author = {Kamerdzhiev, S. P. and Shitov, M. I.}, journal = {JETP Lett.}, volume = {109}, issue = {1}, pages = {69}, year = {2019}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.11334/S0370274X19010132}, note = {[Pisma v ZhETF 109, 65 (2019)]} }