@article{JETPL.93.346, title = {}, author = {, and Tikhonova, O. V.}, journal = {JETP Lett.}, volume = {93}, issue = {6}, pages = {313}, year = {2011}, doi = {}, url = {http://jetpletters.ru/ps/0/article_29181.shtml}, note = {[Pisma v ZhETF 93, 346 (2011)]} }