Brock-Utne, Birgit (1996). Reliability and validity in qualitative research within education in Africa. In: International Reveiw of Education, 42 (6). pp 1-17 (16 p). http://www.jstor.org/stable/pdfplus/3445009.pdf?acceptTC=true.
Bryman, Alan (2004): Social Research methods 2nd edition, Oxford: Oxford University Press. Chapter 1-2, 21-22 (86 p.) Available for loan from the office.
Chalmers, A. F. (1999): What is this thing called science?, Buckingham: Open University Press. (Ch. 1-2, 4-10, 14-16). Available for loan from the office
Kleven, T. A: Validity and validation in qualitative and quantitative research. Nordic Educational research, 2008. Nordisk Pedagogik vol 28. pp. 219-233. http://www.idunn.no/file/ci/14163792/np_2008_03_pdf.pdf.
Oakley, Ann (1981). Interviewing women: a contradition in terms. In: Helen Roberts (ed.): Doing Feminist Research, London: Sage. Chapter 2. (31 p.) . https://hypercontent.hull.ac.uk/short_loan_collection/CASS/35702/Oakley_35702_1134.pdf.
Patton, Michael Quinn (2002): Qualitative Research & Evaluation Methods. 3rd edition, Thousand Oaks, Calif.: Sage Publications. Chapter 1-7 (427 p.).
Vulliamy, Graham, Keith Lewin and David Stephens (1990): Doing Educational Research in Developing Countries: Qualitative Strategies., London: The Falmer Press. . Chapter 1. (20 p.) .