@book { RetargetingalsToolimOnlineMarketing,
    title = "Retargeting als Tool im Online Marketing",
    author = "Markus {Kaspers}",
    year = "2011",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783640968091",
    url = "https://www.hausarbeiten.de/document/175716"
}