@article{PismaZhETF.4.341,
    title = {Self-focusing of Powerful Light Beams by Thermal Effects},
    author = {Litvak, A. G.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {4},
    issue = {9},
    pages = {341},
    year = {1966},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_25031.shtml},
}