@article{PismaZhETF.42.300,
    title = {Production of high-energy muons in extensive air showers from primary $\gamma$ rays},
    author = {Kudryavtsev, V. A. and Ryazhskaya, O. G.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {42},
    issue = {7},
    pages = {300},
    year = {1985},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_21835.shtml},
}