@article{PismaZhETF.9.675,
    title = {Self-focusing of Ultrashort Laser Pulses},
    author = {Abramov, A. A. and Lugovoi, V. N. and Prokhorov, A. M.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {9},
    issue = {12},
    pages = {675},
    year = {1969},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_25427.shtml},
}