@article{JETPL.103.337, title = {}, author = {, and Mavrin, A. A.}, journal = {JETP Lett.}, volume = {103}, issue = {5}, pages = {298}, year = {2016}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X16050027}, note = {[Pisma v ZhETF 103, 337 (2016)]} }