@article{JETPL.102.475, title = {}, author = {, and , and Lutostansky, Yu. S. and Tolokonnikov, S. V.}, journal = {JETP Lett.}, volume = {102}, issue = {7}, pages = {421}, year = {2015}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X15190042}, note = {[Pisma v ZhETF 102, 475 (2015)]} }