@book { WasistEntwicklung,
    title = "Was ist Entwicklung?",
    author = "Tanja {Niemann}",
    year = "2001",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783640009794",
    url = "https://www.hausarbeiten.de/document/102599"
}