@book { WasistdrananderpsychologischenPreisschwelle,
    title = "Was ist dran an der psychologischen Preisschwelle?",
    author = "Heiko {Henn}",
    year = "2010",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783640587094",
    url = "https://www.hausarbeiten.de/document/148322"
}