@book { VariablisierungvonFixkostendurchFacilityManagement, title = "Variablisierung von Fixkosten durch Facility Management", author = "Philipp {Kaufmann}", year = "2002", publisher = "Diplom.de", address = "Hamburg, Germany", doi = "10.3239/9783832453763", url = "https://m.diplom.de/document/220938" }