@article{JETPL.93.442,
    title = {},
    author = {Kovalev, V. M. and Chaplik, A. V.},
    journal = {JETP Lett.},
    volume = {93},
    issue = {7},
    pages = {399},
    year = {2011},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_29232.shtml},
    note = {[Pisma v ZhETF 93, 442 (2011)]}
}