1.
European Commission: Flightpath 2050 Europe’s Vision for Aviation, https://ec.europa.eu/transport/sites/transport/files/modes/air/doc/flightpath2050.pdf, (2011).
2.
Strategic Research & Innovation Agenda 2017 Update, https://www.acare4europe.org/sites/acare4europe.org/files/document/ACARE-Strategic-Research-Innovation-Volume-1.pdf, (2017).
3.
Aerospace Technology Institute: Raising Ambition, Technology Strategy and Portfolio Update 2016, https://www.ati.org.uk/wp-content/uploads/2017/10/Raising-Ambition-ATI-Technology-Strategy-Portfolio-Update-2016.pdf, (2016).
4.
Clean Sky 2: Clean Sky 2 Joint Undertaking Development Plan, http://www.cleansky.eu/sites/default/files/inline-files/51.%20CS2DP%20December%202017.pdf.
5.
NASA: NASA Technology Roadmaps TA15 Aeronautics, https://www.nasa.gov/sites/default/files/atoms/files/2015_nasa_technology_roadmaps_ta_15_aeronautics_final.pdf, (2015).
6.
NASA: NASA Aeronautics Strategic Implementation Plan, https://www.nasa.gov/sites/default/files/atoms/files/sip-2017-03-23-17-high.pdf, (2017).