@article{JETPL.98.371,
    title = {},
    author = {Kovalev, V. M. and Chaplik, A. V.},
    journal = {JETP Lett.},
    volume = {98},
    issue = {6},
    pages = {331},
    year = {2013},
    doi = {},
    url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X13180057},
    note = {[Pisma v ZhETF 98, 371 (2013)]}
}