@book { NormenlehredesZusammenlebens,
    title = "Normenlehre des Zusammenlebens",
    author = "Mahmud {El-Wereny}",
    year = "2018",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/b13325",
    url = "https://www.peterlang.com/document/1110617"
}