@book { UnternehmensentwicklungdurchAkquisitionundKooperation,
    title = "Unternehmensentwicklung durch Akquisition und Kooperation",
    author = "Michael {Müller}",
    year = "1999",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832414856",
    url = "https://m.diplom.de/document/217333"
}