@article{JETPL.97.18, title = {}, author = {Nekrasov, I. A. and Pavlov, N. S. and , }, journal = {JETP Lett.}, volume = {97}, issue = {1}, pages = {15}, year = {2013}, doi = {}, url = {http://jetpletters.ru/ps/0/article_30136.shtml}, note = {[Pisma v ZhETF 97, 18 (2013)]} }