@book { MotivationundKommunikation,
    title = "Motivation und Kommunikation",
    author = "Melanie {Liekfeld}",
    year = "2013",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783656523666",
    url = "https://www.hausarbeiten.de/document/232254"
}