@book { KinderundMedien,
    title = "Kinder und Medien",
    author = "Heike {Krämer}",
    year = "2000",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832424510",
    url = "https://m.diplom.de/document/218249"
}