@book { DerlangeWegzurOEG,
    title = "Der lange Weg zur OEG",
    author = "Ralph {Stephan}",
    year = "2000",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832426019",
    url = "https://m.diplom.de/document/218388"
}