@article{PismaZhETF.73.721,
    title = {Fermion zero modes in  Painlev\'e-Gullstrand black hole},
    author = {Volovik, G. E.},
    journal = {Письма в ЖЭТФ},
    volume = {73},
    issue = {12},
    pages = {721},
    year = {2001},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_9833.shtml},
}