@book { PersonalmarketingimInternet,
    title = "Personalmarketing im Internet",
    author = "Elena {Pentsi}",
    year = "2001",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832431228",
    url = "https://m.diplom.de/document/218827"
}