@article{JETPL.93.516,
    title = {},
    author = {,  and , },
    journal = {JETP Lett.},
    volume = {93},
    issue = {8},
    pages = {470},
    year = {2011},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_29245.shtml},
    note = {[Pisma v ZhETF 93, 516 (2011)]}
}