1. B r i a n E. Barents, Eleventh Annual FAA A v i a t i o n Forecast Conference Proceedings, FAA-APO-86-4, February 1986, pp.44-60.
2. Donald R. Segner, Eleventh Annual FAA A v i a t i o n Forecast Conference Proceedings, FAA-APO-86-4, February 1986, pp.26-42.