@article{JETPL.97.350, title = {}, author = {Il?ichov, L. V.}, journal = {JETP Lett.}, volume = {97}, issue = {6}, pages = {307}, year = {2013}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X13060040}, note = {[Pisma v ZhETF 97, 350 (2013)]} }