@article{JETPL.94.13,
    title = {},
    author = {Achasov, N. N. and Shestakov, G. N.},
    journal = {JETP Lett.},
    volume = {94},
    issue = {1},
    pages = {11},
    year = {2011},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_29422.shtml},
    note = {[Pisma v ZhETF 94, 13 (2011)]}
}