@article{PismaZhETF.12.64,
    title = {Equilibrium Concentration of Positrons in an Optically Thin Relativistic Plasma},
    author = {Bisnovatyi-Kogan, G. S. and Zel'dovich, Ya. B. and Syunyaev, R. A.},
    journal = {Письма в ЖЭТФ},
    volume = {12},
    issue = {2},
    pages = {64},
    year = {1970},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_26229.shtml},
}