@article{JETPL.96.231,
    title = {},
    author = {,  and Volovik, G. E.},
    journal = {JETP Lett.},
    volume = {96},
    issue = {4},
    pages = {215},
    year = {2012},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_29894.shtml},
    note = {[Pisma v ZhETF 96, 231 (2012)]}
}