@article{PismaZhETF.41.267,
    title = {Echos in classical and quantum ensembles with determinate frequencies},
    author = {Dubetskii, B. Ya. and Chebotaev, V. P.},
    journal = {Письма в ЖЭТФ},
    volume = {41},
    issue = {6},
    pages = {267},
    year = {1985},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_22169.shtml},
}