@article{PismaZhETF.24.8,
    title = {Mixing of the frequencies 88.37 THz ($\lambda$ = $3.39\mu$), 125.13 THz ($\lambda$ = 2.39 $\mu$), and 260.1 THz ($\lambda$ = 1.15 $\mu$) in a gas, and production of continuous coherent emission with combined frequency 473.6 THz ($\lambda$ = 0.63 $\mu$)},
    author = {Klement'ev, V. M. and Matyugin, Yu. A. and Chebotaev, V. P.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {24},
    issue = {1},
    pages = {8},
    year = {1976},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_27640.shtml},
}