1. Flick, Uwe (2006) An Introduction to Qualitative Research, 3rd edn (London and others: Sage Publications), esp. pp. 147ff.
2. Fontana, A. and Frey, J. H. (1998) “Interviewing. The Art of Science” in Denzin, N. K. and Lincoln, Y. S. (eds) Collecting and Interpreting Qualitative Materials (Thousand Oaks and others: Sage Publications), pp. 47–78.
3. Kvale, S. and Brinkmann, S. (2009) InterViews: Learning the Craft of Qualitative Research Interviewing, 2nd edn (Thousand Oaks and others: Sage Publications).