1. Adler, P. A., & Adler, P. (1994). Observational techniques. In N. K. Denzin & Y. S. Lincoln (Eds.), Handbook of qualitative research. London: Sage.
2. Altbach, P. G., & De Wit, H. (2015). Internationalization and global tension: Lessons from history. Journal of Studies in Higher Education, 19(1), 4–10.
3. Ary, D., Jacobs, L. C., Sorensen, C. K., & Razavieh, A. (2010). Introduction to research in education (8th, international ed.). Belmont: Wadsworth.
4. Bachman, L. F. (2004). Statistical analyses for language assessment. Cambridge: Cambridge University Press.
5. Barrett, P., & Barrett, L. (2007). The management of academic workloads: Summary report. Leadership Foundation for Higher Education.