@article{JETPL.99.395, title = {}, author = {Chaplik, A. V.}, journal = {JETP Lett.}, volume = {99}, issue = {6}, pages = {346}, year = {2014}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X14060083}, note = {[Pisma v ZhETF 99, 395 (2014)]} }