@article{JETPL.110.493,
    title = {},
    author = {, },
    journal = {JETP Lett.},
    volume = {110},
    issue = {7},
    pages = {505},
    year = {2019},
    doi = {},
    url = {http://jetpletters.ru/ps/dx/10.1134/S0370274X1919010X},
    note = {[Pisma v ZhETF 110, 493 (2019)]}
}