@book { GuerillaMarketing,
    title = "Guerilla-Marketing",
    subtitle = "Grundlagen, Instrumente und Beispiele",
    author = "Christian {Wollscheid}",
    year = "2010",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783836648967",
    url = "https://m.diplom.de/document/227885"
}