@book { ObjektorientierteSoftwareEntwicklung,
    title = "Objektorientierte Software-Entwicklung",
    author = "Sabine {Krämer}",
    year = "2001",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832439910",
    url = "https://m.diplom.de/document/219628"
}