@article{PismaZhETF.6.733,
    title = {Gas Laser Frequency Fluctuations},
    author = {Zaitsev, Yu. N. and Stepanov, D. P.},
    journal = {Письма в ЖЭТФ},
    volume = {6},
    issue = {7},
    pages = {733},
    year = {1967},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_25472.shtml},
}