@book { AltersversorgunggeistigBehinderter,
    title = "Altersversorgung geistig Behinderter",
    author = "Beate {Büttner}",
    year = "1998",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832411138",
    url = "https://m.diplom.de/document/217003"
}