@book { BeihilfenankleineundmittlereUnternehmen,
    title = "Beihilfen an kleine und mittlere Unternehmen",
    author = "Arne {Hertel}",
    year = "2006",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    url = "https://www.peterlang.com/document/1101487"
}