1. Treibhausgasehttp://www.umweltbundesamt.at/umwelt/luft/treibhausgase/
2. Paris Agreementhttp://unfccc.int/files/essential_background/convention/application/pdf/english_paris_agreement.pdf
3. Communication from the Commission. Europe 2020. A Strategy for Smart, Sustainable and Inclusive Growthhttp://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=COM:2010:2020:FIN:EN:PDF
4. Amazon to Step up UK Tests of Delivery Droneshttp://www.telegraph.co.uk/technology/2016/07/26/amazon-to-step-up-uk-tests-of-delivery-drones/
5. Drone Delivery: DHL ‘Parcelcopter’ Flies to German Islehttp://www.reuters.com/article/us-deutsche-post-drones-idUSKCN0HJ1ED20140924