@book { DasvergaberechtlicheInhouseGeschft,
    title = "Das vergaberechtliche Inhouse-Geschäft",
    author = "Jannis {Konstas}",
    year = "2021",
    publisher = "Meidenbauer",
    address = ", Germany",
    url = "https://www.peterlang.com/document/1098684"
}