@article{PismaZhETF.16.102,
    title = {The Problem of the $K_L \to 2\mu$ Decay and $\mu-mesic$ Atoms},
    author = {Zakharov, V. I. and Okun', L. B.},
    journal = {Письма в ЖЭТФ},
    volume = {16},
    issue = {2},
    pages = {102},
    year = {1972},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_26741.shtml},
}