@article{PismaZhETF.13.440,
    title = {Resonatorless Parametric Light Generator Using an $\alpha-HI0_3$ Crystal},
    author = {Kovrigin, A. I. and Nikles, P. V.},
    journal = {Письма в ЖЭТФ},
    volume = {13},
    issue = {8},
    pages = {440},
    year = {1971},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_24305.shtml},
}