@article{PismaZhETF.21.91,
    title = {Existence of heavy particles in gauge field theories},
    author = {Tyupkin, Yu. S. and Fateev, V. A. and Shvarts, A. S.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {21},
    issue = {1},
    pages = {91},
    year = {1975},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_22240.shtml},
}