@article{JETPL.102.823, title = {}, author = {Ratnikov, P. V. and Silin, A. P.}, journal = {JETP Lett.}, volume = {102}, issue = {11}, pages = {713}, year = {2015}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X15230046}, note = {[Pisma v ZhETF 102, 823 (2015)]} }