@article{PismaZhETF.37.188,
    title = {Spectroscopy of two-photon transitions in $C_2H_4$ using the degenerate four-photon interaction method},
    author = {Varakin, V. N. and Gordienko, V. M.},
    journal = {Письма в ЖЭТФ},
    volume = {37},
    issue = {4},
    pages = {188},
    year = {1983},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_22769.shtml},
}