@book { HarryPotter,
    title = "Harry Potter",
    subtitle = "Auf den Spuren eines zauberhaften Bestsellers",
    author = "Sandra {Wilfinger-Bak}",
    year = "2004",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1097885"
}