@article{JETPL.102.444, title = {}, author = {Chirkin, A. S.}, journal = {JETP Lett.}, volume = {102}, issue = {6}, pages = {404}, year = {2015}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X15180162}, note = {[Pisma v ZhETF 102, 444 (2015)]} }