@book { DieUntersuchungderWohnformGatedCommunities,
    title = "Die Untersuchung der Wohnform Gated Communities",
    author = "Alexandra {Schmidt}",
    year = "2004",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832478865",
    url = "https://m.diplom.de/document/223139"
}