@book{karmarsch+und+heeren+039+s+technisches+woerterbuch+bd+9+telephon+ultrachinin,
    author = {Karmarsch, Karl i Heeren, Friedrich},
    title = {Karmarsch und Heeren's Technisches Wörterbuch. Bd. 9, Telephon. - Ultrachinin},
    address = {Prag},
    publisher = {Verlag von A. Haase},
    date = {1888}
}