@book { ElectronicProcurement,
    title = "Electronic Procurement",
    subtitle = "Internetbasierte Optimierung von Einkaufs- und Beschaffungsprozessen",
    author = "Robert {Stocki}",
    year = "2001",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832432317",
    url = "https://m.diplom.de/document/218921"
}