@article{PismaZhETF.8.357,
    title = {Optical Properties and Stimulated Emission of $Nd^{3+}$ in Fluor-apatite},
    author = {Bruk, Z. M. and Voron'ko, Yu. K. and Maksimova, G. V. and Osiko, V. V. and Prokhorov, A. M. and Shpilov, K. F. and Shcherbakov, I. A.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {8},
    issue = {7},
    pages = {357},
    year = {1968},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_26014.shtml},
}