@article{JETPL.99.483, title = {}, author = {Yakushkin, E. D.}, journal = {JETP Lett.}, volume = {99}, issue = {7}, pages = {415}, year = {2014}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X14070121}, note = {[Pisma v ZhETF 99, 483 (2014)]} }