@article{PismaZhETF.17.337,
    title = {Self-focusing  of $C0_2$  Laser  Radiation  in   Resonantly Absorbing  Gases},
    author = {Karlov, N. V. and Karpov, N. A. and Petrov, Yu. N. and Stel 'nfakh, O. M.},
    journal = {Письма в ЖЭТФ},
    volume = {17},
    issue = {7},
    pages = {337},
    year = {1973},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_23559.shtml},
}