@article{PismaZhETF.16.355,
    title = {Critical Charge in the Two-center Problem},
    author = {Popov, V. S.},
    journal = {Письма в ЖЭТФ},
    volume = {16},
    issue = {6},
    pages = {355},
    year = {1972},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_26847.shtml},
}