@article{PismaZhETF.28.274,
    title = {Contribution of instantons to the correlation functions of a Heisenberg ferromagnet},
    author = {Frolov, I. V. and Shvarts, A. S.},
    journal = {Письма в ЖЭТФ},
    volume = {28},
    issue = {5},
    pages = {274},
    year = {1978},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_24138.shtml},
}