1. ICAO Doc 9859 3rd ed. Fig. 4-1.
2. ICAO Doc 9859 2rd ed. 9.6.
3. U.S. Department of Transportation, “FAA needs to improve risk
assessment process for its Air Transportation Oversight System,” FAA Report
Number AV-2011-026, 16 Dec., 2010.
4. FAA, “Acquisition Strategy Paper - System Approach for Safety
Oversight (SASO)”, 2004.
5. EASA, Practice for risk-based oversight, 2016.