@article{PismaZhETF.21.678,
    title = {Classical spin and Grassmann algebra},
    author = {Berezin, F. A. and Marinov, M. S.},
    journal = {Письма в ЖЭТФ},
    volume = {21},
    issue = {11},
    pages = {678},
    year = {1975},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_22521.shtml},
}