@book { bungsbuchMathematikinderBWL,
    title = "Übungsbuch Mathematik in der BWL",
    author = "Korbinian {Blanckenburg}",
    year = "2019",
    publisher = "Vahlen",
    address = "München, Deutschland",
    url = "https://vahlen.openpublishing.com/document/1221337"
}