@article{JETPL.94.335, title = {}, author = {Ramazanov, M. K.}, journal = {JETP Lett.}, volume = {94}, issue = {4}, pages = {311}, year = {2011}, doi = {}, url = {http://jetpletters.ru/ps/0/article_29496.shtml}, note = {[Pisma v ZhETF 94, 335 (2011)]} }