@article{JETPL.100.288, title = {}, author = {Chaplik, A. V.}, journal = {JETP Lett.}, volume = {100}, issue = {4}, pages = {262}, year = {2014}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X14160097}, note = {[Pisma v ZhETF 100, 288 (2014)]} }