9Walter P J. Forecasting the demand for air transportation services: an analysis of the forecasts published by the international civil aviation organization, boeing, McDonnell douglas, and airbus industrie [ J ]. Transportation Research Part A: Policy and Practice, 1995, 29(Issue 1) :49.
10Cline R C, Ruhl T A, Gosling G D, et al. Air transportation demand forecasts in emerging market economies: a case study of the kyrgyz republic in the former soviet union[J]. Journal of Air Transport Management, 1998, 4(Issue 1): 11.