1. Bakhtin, M. M. (1986). Speech genres and other late essays. Austin, TX: University of Texas Press.
2. Blake, G., & Bly, R. W. (1993). The elements of technical writing. New York: McMillan.
3. Britton, W. (1965). What is technical writing? College Composition and Communication, 16(2), 113–116.
4. Brown, P., & Levinson, S. (1978). Politeness. Some universals in language usage. Cambridge, UK: Cambridge University Press.
5. Chen, C., & Zhang, L. J. (2017). An intercultural analysis of the use of hedging by Chinese and Anglophone academic English writers. Applied Linguistics Review, 8(1), 1–34. http://hdl.handle.net/2292/33681