@article{PismaZhETF.11.177,
    title = {Thermal Self-focusing of Laser Radiation in Media with Negative dn/dT},
    author = {Zverev, G. M. and Levchuk, E. A. and Maldutis, E. K. and Pashkov, V. A.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {11},
    issue = {3},
    pages = {177},
    year = {1970},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_26084.shtml},
}