@book { PaulGerhardtsKirchenlieder,
    title = "Paul Gerhardts Kirchenlieder",
    author = "Ryszard {Ziaja}",
    year = "2015",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-05347-0",
    url = "https://www.peterlang.com/document/1049292"
}