1. American Psychological Association. (2001). Publication manual of the American Psychological Association (5th ed.). Washington, DC: American Psychological Association.
2. Booth, W., Colomb, G., & Williams, J. (1995). The craft of research. Chicago: The University of Chicago Press.
3. Bronson, D., & Davis, T. (2012). Finding and evaluating evidence: Systematic reviews and evidence-based practice. New York: Oxford University Press.
4. Carpenter, H. S. (2008). A behavioural and electrophysiological investigation of different aptitudes for L2 grammar in learners equated for proficiency level. Ph.D. dissertation, Georgetown University.
5. Cooper, H. (2016). Research synthesis and meta-analysis: A step-by-step approach (5th ed.). Thousand Oaks, CA: SAGE.