@book { DasFranchiseSystem,
    title = "Das Franchise-System",
    subtitle = "Handbuch für Franchisegeber und Franchisenehmer",
    author = "Jürgen {Nebel} and Albrecht {Schulz} and Eckhard {Flohr}",
    year = "2012",
    publisher = "Vahlen",
    address = "München, Deutschland",
    url = "https://vahlen.openpublishing.com/document/1220813"
}