@article{JETPL.109.639,
    title = {},
    author = {,  and ,  and , },
    journal = {JETP Lett.},
    volume = {109},
    issue = {9},
    pages = {620},
    year = {2019},
    doi = {},
    url = {http://jetpletters.ru/ps/dx/10.1134/S0370274X19090145},
    note = {[Pisma v ZhETF 109, 639 (2019)]}
}