@book { EarlyStageInvestmentsinNewTechnologyBasedFirms,
    title = "Early Stage Investments in New Technology Based Firms",
    author = "Holger {Ludewig}",
    year = "1999",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832412142",
    url = "https://m.diplom.de/document/217133"
}