@book { MartinLuther,
    title = "Martin Luther ",
    author = "Heiko {Suhr}",
    year = "2011",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783656082590",
    url = "https://www.hausarbeiten.de/document/183803"
}