@article{JETPL.97.266, title = {}, author = {, and , and , and Xue, Z.-Y.}, journal = {JETP Lett.}, volume = {97}, issue = {4}, pages = {239}, year = {2013}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X13040140}, note = {[Pisma v ZhETF 97, 266 (2013)]} }