@article{JETPL.93.813, title = {}, author = {Dolganov, P. V. and , and Dolganov, V. K.}, journal = {JETP Lett.}, volume = {93}, issue = {12}, pages = {731}, year = {2011}, doi = {}, url = {http://jetpletters.ru/ps/0/article_29415.shtml}, note = {[Pisma v ZhETF 93, 813 (2011)]} }