@article{PismaZhETF.25.68,
    title = {Determination of the $\pi \pi$ scattering length in the effective-radius approximation},
    author = {Kartamyshev, A. A. and Makar'in, V. K. and Mukhin, K. N. and Patarkin, O. O. and Sulkovskaya, M. M. and Sustarov, A. F.},
    journal = {Письма в ЖЭТФ},
    volume = {25},
    issue = {1},
    pages = {68},
    year = {1977},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_21019.shtml},
}