@book { WerbungfrSenioren,
    title = "Werbung für Senioren",
    author = "Julia {Colella}",
    year = "2013",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783656349495",
    url = "https://www.hausarbeiten.de/document/207676"
}