@article{JETPL.107.519,
    title = {},
    author = {Ryzhkin, M. I. and Ryzhkin, I. A.},
    journal = {JETP Lett.},
    volume = {107},
    issue = {8},
    pages = {500},
    year = {2018},
    doi = {},
    url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X18080106},
    note = {[Pisma v ZhETF 107, 519 (2018)]}
}