@article{PismaZhETF.12.363,
    title = {Thermal Self-focusing and Breakdown Induced in NaCl, KBr, and Csl Crystals by $CO_2-laser$ Radiation},
    author = {Karlov, N. V. and Kuz'min, G. P. and Prokhorov, A. M.},
    journal = {Письма в ЖЭТФ},
    volume = {12},
    issue = {7},
    pages = {363},
    year = {1970},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_26328.shtml},
}