@article{PismaZhETF.12.486,
    title = {Feasibility of Producing an Inverted Medium by Photoionzation of the Inner Electrons in Atoms},
    author = {Rozanov, V. B.},
    journal = {Письма в ЖЭТФ},
    volume = {12},
    issue = {10},
    pages = {486},
    year = {1970},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_26365.shtml},
}