@article{PismaZhETF.8.106,
    title = {Phenomenological Theory of $K^0$ Mesons and the Non-exponential Character of the Decay},
    author = {Khalfin, L. A.},
    journal = {Письма в ЖЭТФ},
    volume = {8},
    issue = {2},
    pages = {106},
    year = {1968},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_25921.shtml},
}