@book { GeopolitikundStrategieamBeginndes21Jahrhunderts,
    title = "Geopolitik und Strategie am Beginn des 21. Jahrhunderts",
    author = "Andrea K. {Riemer}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1101409"
}