@article{PismaZhETF.58.868,
    title = {Population inversion and amplification of far-IR radiation at cyclotron resonance of heavy hot holes in germanium},
    author = {Vorob'ev, L. E.},
    journal = {Письма в ЖЭТФ},
    volume = {58},
    issue = {11},
    pages = {868},
    year = {1993},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_18020.shtml},
}