1. Preece, J., Rogers, Y., Sharp, H., Benyon, D., Holland, S. and Carey, T., Human-Computer Interaction. The Open University. Addison Wesley, 1994.
2. Rubin, J. “Handbook of usability testing”. John Wiley & Sons. Inc. New York, 1994.
3. Lee, S. H. Usability testing for Developing Effective Interactive Multimedia Software: Concepts, Dimensions and Procedures. Educational Technology & Society, vol. 2, n. 2, 1999.
4. Benyon, D., Davies, G., Keller, L. and Rogers, Y. A Guide to Usability-Usability Now!. Milton Keynes: The Open University, 1990.
5. Catenazzi, N., Aedo, I., Díaz, P. and Sommaruga, L. The evaluation of electronic books: Guidelines from two practical experiences. Journal of Educational Multimedia and Hypermedia. 6(1), pp. 91–114, 1997.