1. John, C., Roger, C., Simeon, K., Cherie, L.: Inclusive Design -Design for the whole population. Springer, Great Britain (2003)
2. Robert, C.: Participatory Workshops: A Sourcebook of 21 Sets of Ideas and Activities. Earthscan Pubns Ltd (2002)
3. Merton, R.K.: The Focused Interview and Focus Groups: Continuities and Discontinuities. Public Opinion Quarterly 51, 550–556 (1987)
4. Richard, A.K.: Focus Groups: A Practical Guide for Applied Research, 3rd edn. Sage Pubns, Thousand Oaks (2000)
5. Spradley, J.P.: Participant Observation. Rinehart and Winston, New York. Holt (1980)