@article{PismaZhETF.6.966,
    title = {Nonlinear Negative Absorption of Light in an Inhomogeneously Inverted Semiconductor},
    author = {Rivlin, L. A.},
    journal = {Письма в ЖЭТФ},
    volume = {6},
    issue = {11},
    pages = {966},
    year = {1967},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_25549.shtml},
}