@book { MartinLutherKing,
    title = "Martin Luther King",
    author = "Kira {Herzog}",
    year = "2012",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783656169727",
    url = "https://www.hausarbeiten.de/document/191820"
}