@article{JETPL.93.493, title = {}, author = {Gusev, A. I.}, journal = {JETP Lett.}, volume = {93}, issue = {8}, pages = {447}, year = {2011}, doi = {}, url = {http://jetpletters.ru/ps/0/article_29241.shtml}, note = {[Pisma v ZhETF 93, 493 (2011)]} }