1. Air Transport Action Group (ATAG): Benefits Beyond Borders. ATAG, Geneva (2018)
2. PwC, A4E: The Economic Impact of ATC: Strikes in Europe. PwC, London (2016)
3. CODA DIGEST: All-causes delay and cancellations to air transport in Europe. EUROCONTROL (2018)
4. Billette de Villemeur, E., Ivaldi, M., Quinet, E., Urdanoz, M.: The social cost of air traffic delays (Dec 2014)
5. ATAG - Air Transport Action Group: Revolutionising air traffic management—practical steps to accelerating airspace efficiency in your region (2012)