1. The Delphi Method, “Futures Research Methodology V2”, CD ROM, the Millennium Project, American Council for the United Nations University;Gordon,2003
2. Principles of Forecasting (International Series in Operations Research and Management Science);Armstrong,2001
3. http://www.crab.rutgers.edu/~goertzel/futuristmethods.htm.
4. “Futuring: the Exploration of the Future”;Cornish,2005