@book { DevelopmentofanITSecurityPerformanceMeasurementSystem,
    title = "Development of an IT-Security Performance Measurement System",
    author = "Michael {Scheer}",
    year = "2003",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832467883",
    url = "https://m.diplom.de/document/222142"
}