@book { ImmobilienanlageninderAssetAllocation,
    title = "Immobilienanlagen in der Asset Allocation",
    author = "Martin {Sachsenmaier}",
    year = "1999",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832418793",
    url = "https://m.diplom.de/document/217729"
}