1. 8 Clarke L. and Irving J. (1987). Report on investigations into aircraft with measured height deviations of 300 ft or more (‘rogue’ aircraft). Report No. 2O7, EUROCONTROL, Brussels.
2. 4 Nagaoka S. (1987). Estimation of the probability of vertical overlap of a proximate pair of aircraft based on NAMS data. RGCSP-WG/B-WP/55, January. ICAO, Montreal.