@article{JETPL.95.390, title = {}, author = {Val?kov, V. V. and , }, journal = {JETP Lett.}, volume = {95}, issue = {7}, pages = {350}, year = {2012}, doi = {}, url = {http://jetpletters.ru/ps/0/article_29672.shtml}, note = {[Pisma v ZhETF 95, 390 (2012)]} }