1. Brundtland GH (1987) Report of the World Commision on Environment and Development “Out CommonFuture”, pp. 11–17,
https://sswm.info/sites/default/files/reference_attachments/UN%20WCED%201987%20Brundtland%20Report.pdf
2. Sledsens T (1998) Sustainable aviation: the need for a European environmental aviation charge, T&E 98(1). European Federation for Transport and Environment, Brussels
3. IPCC (1999) IPCC special report. Aviation and the global atmosphere: summary for policymakers.
https://www.ipcc.ch/report/aviation-and-the-global-atmosphere-2/
4. Adams WM The future of sustainability: re-thinking environment and development in the twenty-first century. Revised: 22 May 2006,
http://cmsdata.iucn.org/downloads/iucn_future_of_sustanability.pdf
. Accessed 10 Sep 2018
5. Paschek F (2015) Urban sustainability in theory and practice-circles of sustainability. Town Plan Rev 86(6):745