@article{PismaZhETF.47.181,
    title = {Two-loop contribution to the four-point function in superstring theory},
    author = {Morozov, A.},
    journal = {Письма в ЖЭТФ},
    volume = {47},
    issue = {4},
    pages = {181},
    year = {1988},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_16488.shtml},
}