@book { EinBeitragzurKonjunkturtheorieoffenerVolkswirtschaften,
    title = "Ein Beitrag zur Konjunkturtheorie offener Volkswirtschaften",
    author = "Bernhard {Fippel}",
    year = "2021",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1087341"
}