@article{PismaZhETF.42.340,
    title = {Multiloop contribution to string theory},
    author = {Baranov, M. A. and Shvarts, A. S.},
    journal = {Письма в ЖЭТФ},
    volume = {42},
    issue = {8},
    pages = {340},
    year = {1985},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_21849.shtml},
}