@book { PrivateMilitrunternehmenimVlkerrecht,
    title = "Private Militärunternehmen im Völkerrecht",
    author = "Martin {Niewerth}",
    year = "2021",
    publisher = "Meidenbauer",
    address = ", Germany",
    url = "https://www.peterlang.com/document/1105808"
}