@book { EmissionszertifikatehandelinderLuftfahrt,
    title = "Emissionszertifikatehandel in der Luftfahrt",
    author = "Matthias {Scharfe}",
    year = "2013",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783656477587",
    url = "https://www.hausarbeiten.de/document/231506"
}