@article{JETPL.109.219,
    title = {},
    author = {Volkov, M. K. and Pivovarov, A. A.},
    journal = {JETP Lett.},
    volume = {109},
    issue = {4},
    pages = {222},
    year = {2019},
    doi = {},
    url = {http://jetpletters.ru/ps/dx/10.1134/S0370274X19040027},
    note = {[Pisma v ZhETF 109, 219 (2019)]}
}