Indirect illocution is an illocutionary act in which the speaker expresses another illocutionary force other than that literally expressed in the utterance, by relying on:
Searle, John, and Daniel Vanderveken. 1985.Foundations of illocutionary logic. Cambridge, England: Cambridge University.
Searle, John. 1979.Expression and meaning: Studies in the theory of speech acts. Cambridge, England: Cambridge University.
Levinson, Stephen C. 1983.Pragmatics. Cambridge, England: Cambridge University.