@article{PismaZhETF.13.359,
    title = {WKB Method for a Strong Coulomb Field},
    author = {Krainov, V. I.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {13},
    issue = {7},
    pages = {359},
    year = {1971},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_24262.shtml},
}