@book { SystemsThinkingViewontheSituationofUnemploymentintheUSA,
    title = "Systems Thinking View on the Situation of Unemployment in the USA",
    author = "Roland {Schuster}",
    year = "2003",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832471545",
    url = "https://m.diplom.de/document/222465"
}