@book { IstTugendnotwendigzumGlck,
    title = "Ist Tugend notwendig zum Glück?",
    author = "Dana {Michaelis}",
    year = "2013",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783656501039",
    url = "https://www.hausarbeiten.de/document/233485"
}