@article{PismaZhETF.48.516,
    title = {$(\alpha')^2$ correction to the effective action of a boson string from the three-loopy $\beta$ function of a nonlinear $\sigma$ model with torsion},
    author = {Ketov, S. V. and Samolov, A. I.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {48},
    issue = {10},
    pages = {516},
    year = {1988},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_16782.shtml},
}