1. A Study of Near Midair Collisions in U.S. Terminal Airspace;Billings,1980
2. Predicting nuclear incidents;Chow;J. of Forecasting,1988
3. NMAC Database;FAA,1986
4. FAA Air Traffic Activity FY 1983–1986;FAA,1986
5. Air Traffic Fact Book 1983–1986;FAA,1986