@article{PismaZhETF.35.266,
    title = {Decays of $\pi ^\pm$  mesons involving axions and massless axions: $\pi\to l+\nu_l+a(a')$},
    author = {Ansel'm, A. A. and Lobashev, V. M. and Ural'tsev, N. G.},
    journal = {Письма в ЖЭТФ},
    volume = {35},
    issue = {6},
    pages = {266},
    year = {1982},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_19918.shtml},
}