@article{JETPL.104.201,
    title = {},
    author = {Volovik, G. E.},
    journal = {JETP Lett.},
    volume = {104},
    issue = {3},
    pages = {201},
    year = {2016},
    doi = {},
    url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X16150121},
    note = {[Pisma v ZhETF 104, 201 (2016)]}
}