@book { OskarRosenfeldundOskarSinger,
    title = "Oskar Rosenfeld und Oskar Singer",
    author = "Sascha {Feuchert}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1097127"
}