@book { LuftfahrtClusterHamburgNorddeutschland,
    title = "Luftfahrt-Cluster Hamburg/Norddeutschland",
    author = "Wilhelm {Pfähler} and Alf Erko {Lublinski}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1095760"
}