@book { DieSorgeerklrungengem1626aINr1BGB,
    title = "Die Sorgeerklärungen gemäß § 1626a I Nr. 1 BGB",
    author = "Friderike {Weiß}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1099546"
}