@book { HansGeorgBertram,
    title = "Hans Georg Bertram",
    subtitle = "Komponist und Kirchenmusiker",
    author = "Susanne {Haist}",
    year = "1999",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1088393"
}