@article{JETPL.106.208,
    title = {},
    author = {Ruban, V. P.},
    journal = {JETP Lett.},
    volume = {106},
    issue = {4},
    pages = {223},
    year = {2017},
    doi = {},
    url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X17160044},
    note = {[Pisma v ZhETF 106, 208 (2017)]}
}