1. Accessibility Guidelines for Buildings and Facilities (ADAAG),2002
2. Statistical Abstract of the United States: 2004–2005,2004
3. Accredited Standard on Safety Colors, Signs, Symbols, Labels, and Tags, Z535.1-5,1991
4. Wayfinding: People, Signs, and Architecture;Arthur,1992
5. Bailey, H.J., Milheim, W.D., 1991. A comprehensive model for deigning interactive video based materials. In: Proceeding for the Night Conference on Interactive Instruction Delivery at the 2991 Society for Applied Learning Technology Conference, Orlando, FL.