@book { InhaltundBedeutungdesFirmenkundengeschfts,
    title = "Inhalt und Bedeutung des Firmenkundengeschäfts",
    author = "Markus {Schmid}",
    year = "2003",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832468347",
    url = "https://m.diplom.de/document/222181"
}