@book { ExterneEffekteinderUmweltkonomie,
    title = "Externe Effekte in der Umweltökonomie",
    author = "Friedrich {Wacker}",
    year = "2012",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783656338567",
    url = "https://www.hausarbeiten.de/document/206674"
}