@article{PismaZhETF.34.412,
    title = {Weinberg angle and the proton lifetime in asymptotically free and supersymmetric grand unification models},
    author = {Fradkin, E. S. and Fradkina, T. E.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {34},
    issue = {7},
    pages = {412},
    year = {1981},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_23222.shtml},
}