@article{PismaZhETF.12.371,
    title = {Three-photbn Ionization of a Helium Atom in the Excited 2S State},
    author = {Bakos, J. and Kantor, J. and Kiss, A.},
    journal = {Письма в ЖЭТФ},
    volume = {12},
    issue = {7},
    pages = {371},
    year = {1970},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_26330.shtml},
}