@book { GeschftsprozessmodellierungStepbyStep,
    title = "Geschäftsprozessmodellierung Step by Step",
    author = "Angelika {Ludwig} and Christine {Würstl}",
    year = "2002",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783832455941",
    url = "https://m.diplom.de/document/221079"
}