1. 2 Chisnell D and Rubin J (2008)Handbook of Usability Testing: how to plan, design, and conduct effective tests(2e). Wiley: New York, NY.
2. Dumas JS and Redish JC (1999)A Practical Guide to Usability Testing(2e). Intellect: Bristol, UK.
3. Nielsen J (1994)Usability Engineering. Morgan Kaufmann Publishers: San Francisco, CA.