@article{JETPL.108.541,
    title = {},
    author = {, },
    journal = {JETP Lett.},
    volume = {108},
    issue = {8},
    pages = {508},
    year = {2018},
    doi = {},
    url = {http://jetpletters.ru/ps/dx/10.1134/S0370274X18200031},
    note = {[Pisma v ZhETF 108, 541 (2018)]}
}