@article{PismaZhETF.17.216,
    title = {Dispersion   Relations   and Charge  Exchange   Reaction  $\pi^-p\to \pi^0n$   at High Energies},
    author = {Solov'ev, L. D. and Shchelkachev, A. V.},
    journal = {Письма в ЖЭТФ},
    volume = {17},
    issue = {4},
    pages = {216},
    year = {1973},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_23522.shtml},
}