@book { BeitrgezurregionalenNamenkunde,
    title = "Beiträge zur regionalen Namenkunde",
    author = "Karl-Ernst {Sommerfeldt}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1096035"
}