@article{PismaZhETF.39.214,
    title = {Method of eigenfunctions and noneigenfunctions in the theory of the beam-plasma instability of a spatially bounded electron beam},
    author = {Popkov, N. G.},
    journal = {Письма в ЖЭТФ},
    volume = {39},
    issue = {5},
    pages = {214},
    year = {1984},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_19460.shtml},
}