@article{JETPL.106.312,
    title = {},
    author = {Tkachenko, O. A. and Tkachenko, V. A.},
    journal = {JETP Lett.},
    volume = {106},
    issue = {5},
    pages = {336},
    year = {2017},
    doi = {},
    url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X17170106},
    note = {[Pisma v ZhETF 106, 312 (2017)]}
}