@book { FeasibilityStudiesforHotels,
    title = "Feasibility Studies for Hotels",
    author = "Wolfgang {Fercher}",
    year = "2006",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832499143",
    url = "https://m.diplom.de/document/225031"
}