1. Baker, Paul. 2009. Contemporary corpus linguistics. London: Continuum.
2. Barlow, Michael. 2000. Corpus of spoken professional American English. CD-ROM version. Houston, TX: Athelstan.
3. Biber, Douglas. 1988. Variation across speech and writing. Cambridge: Cambridge University Press.
4. Biber, Douglas, Stig Johansson, Geoffrey Leech, Susan Conrad & Edward Finegan. 1999. The Longman grammar of spoken and written English. London: Longman.
5. Birner, Betty. 1996. The discourse function of inversion in English. New York: Garland.