@article{PismaZhETF.17.428,
    title = {Surface   Excitons   of Electron-hole  Type and  Collective  Phenomena Associated with  Them},
    author = {Ginzburg, V. I. and Kelle, V. V.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {17},
    issue = {8},
    pages = {428},
    year = {1973},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_23586.shtml},
}