@book { ITSystemmanagement,
    title = "IT-Systemmanagement",
    author = "Erwin {Salm}",
    year = "2007",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783836602532",
    url = "https://m.diplom.de/document/228825"
}