@book { HybrideHeizundKhlsystemeimWohnungsbau,
    title = "Hybride Heiz- und Kühlsysteme im Wohnungsbau",
    author = "Helmuth {Duve}",
    year = "1999",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832419172",
    url = "https://m.diplom.de/document/217765"
}