@article{PismaZhETF.44.209,
    title = {Quantization of the mass of a black hole in string theory},
    author = {Kogan, Ya. I.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {44},
    issue = {4},
    pages = {209},
    year = {1986},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_21024.shtml},
}