@article{PismaZhETF.33.48,
    title = {Nonlinear defocusing of a focused beam: a fine beam from the focus},
    author = {Askar'yan, G. A. and Mukhamadzhanov, M. A.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {33},
    issue = {1},
    pages = {48},
    year = {1981},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_22929.shtml},
}