@book { CallawayBusinessCaseStudy,
    title = "Callaway Business Case Study",
    author = "Nihat {Canak}",
    year = "2006",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638575003",
    url = "https://www.hausarbeiten.de/document/64769"
}