@article{JETPL.106.523,
    title = {},
    author = {Yakushkin, E. D.},
    journal = {JETP Lett.},
    volume = {106},
    issue = {8},
    pages = {544},
    year = {2017},
    doi = {},
    url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X17200127},
    note = {[Pisma v ZhETF 106, 523 (2017)]}
}