@article{PismaZhETF.48.633,
    title = {Characteristic-electron-energy-loss spectroscopy of an $YBa_2Cu_3O_{7-\delta}$ superconducting ceramic},
    author = {Kireev, I. V. and Mikheeva, M. N. and Nazin, V. G. and Svishchev, A. V.},
    journal = {Письма в ЖЭТФ},
    volume = {48},
    issue = {11},
    pages = {633},
    year = {1988},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_16813.shtml},
}