@article{JETPL.97.344,
    title = {},
    author = {Volovik, G. E. and Zubkov, M. A.},
    journal = {JETP Lett.},
    volume = {97},
    issue = {6},
    pages = {301},
    year = {2013},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_30232.shtml},
    note = {[Pisma v ZhETF 97, 344 (2013)]}
}