@article{PismaZhETF.2.139,
    title = {Monotonicity of the Decay of Unstable Particles Corresponding to an n-order Pole},
    author = {Khalfin, L. A.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {2},
    issue = {3},
    pages = {139},
    year = {1965},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_24483.shtml},
}