@article{PismaZhETF.1.33,
    title = {Selective excitation of rare-earth ion centers in crystals},
    author = {Voron'ko, Yu. K. and Kaminskii, A. A. and Osiko, V. V. and Prokhorov, A. M.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {1},
    issue = {4},
    pages = {33},
    year = {1965},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_24420.shtml},
}