1. Åkerlind, G. S. (2005). Variation and commonality in phenomenographic research methods. Higher Education Research and Development, 24(4), 321–334. https://doi.org/10.1080/07294360500284672
2. Alsop, G., & Tompsett, C. (2006). Making sense of ‘pure’ phenomenography in information and communication technology in education. Research in Learning Technology, 14(3). https://doi.org/10.3402/rlt.v14i3.10966.
3. Booth, S. (2008). Researching learning in networked learning—phenomenography and variation theory as empirical and theoretical approaches. In Proceedings of the 6th International Conference on Networked Learning (Vol. Halkidiki,). http://www.networkedlearningconference.org.uk/past/nlc2008/Info/confpapers.htm.
4. Costello, J. (2012). Perceptions of guest lecturers’ impact on online learning communities. In V. Hodgson, C. Jones, M. de Laat, D. McConnell, T. Ryberg, & P. Sloep (Eds.), 8th International Conference on Networked Learning (pp. 482–487). Maastrict, Netherlands. https://www.lancaster.ac.uk/fss/organisations/netlc/past/nlc2012/info/confpapers.html.
5. Dahlin, B. (2007). Enriching the theoretical horizons of phenomenography, variation theory, and learning studies. Scandinavian Journal of Educational Research, 51(4), 327–346. https://doi.org/10.1080/00313830701485437