James, Deborah. 1972. Some aspects of the syntax and semantics of interjections. Papers from the Eighth Regional Meeting of the Chicago Linguistic Society, ed. by Paul M. Peranteau, Judith N. Levi and Gloria C. Phares. 162–72. Chicago: Chicago Linguistic Society.
Rose, Ralph Leon. 1998. The communicative value of filled pauses in spontaneous speech. M.A. thesis, University of Birmingham.
Sacks, Harvey, Emanuel A. Schegloff & Gail Jefferson. 1974. A simplest systematic for the organization of turn-taking for conversation. Language 50(4): 696–735.
Schiffrin, Deborah. 1987. Discourse Markers. Cambridge: Cambridge University Press.