@article{PismaZhETF.66.747,
    title = {Perturbation theory for the $\pi^+\pi^-$ atom},
    author = {Lyubovitskij, V. E. and Lipartia, E. Z. and Rusetsky, A. G.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {66},
    issue = {12},
    pages = {747},
    year = {1997},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_15547.shtml},
}