@book { DieMesseinihrerFunktionalsMarketinginstrument,
    title = "Die Messe in ihrer Funktion als Marketinginstrument",
    author = "Alexander {Hörr}",
    year = "2006",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638458771",
    url = "https://www.hausarbeiten.de/document/49410"
}