1. Ayers, D. (1986). English words from Latin and Greek Elements. 2nd ed. The University of Arizona Press.
2. Bauer, L. (1983). English word-formation. Cambridge university press. https://doi.org/10.1017/CBO9781139165846
3. Carter, R. a. (1988). Vocabulary and Language Teaching. Allen and Unwin.
4. Creswell, J. W., & Creswell, J. D. (2017). Research design: Qualitative, quantitative, and mixed methods approaches. . Sage publications.
5. Davis, N. B. (1979). Vocabulary improvement: A program for self-instruction. McGraw-Hill College.