@book { ErlingderMutigeWikingerRoman,
    title = "Erling der Mutige: Wikinger Roman",
    author = "R. M. {Ballantyne}",
    year = "2023",
    publisher = "Uksak E-Books",
    address = "Lengerich, Deutschland",
    url = "https://uksakebooks.grin.com/document/1359530"
}