@article{JETPL.103.801, title = {}, author = {Chaplik, A. V.}, journal = {JETP Lett.}, volume = {103}, issue = {11}, pages = {708}, year = {2016}, doi = {}, url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X16110096}, note = {[Pisma v ZhETF 103, 801 (2016)]} }