@article{PismaZhETF.21.45,
    title = {New mechanism of self-focusing of light in a gas medium in the presence of absorbing centers},
    author = {Kopytin, Yu. D. and Khmelevtsov, S. S.},
    journal = {Письма в ЖЭТФ},
    volume = {21},
    issue = {1},
    pages = {45},
    year = {1975},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_22256.shtml},
}