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3. Bromberger, S.: 1992, On What We Know We Don't Know. Explanation, Theory, Linguistics, and How Questions Shape Them, The University of Chicago Press, Chicago and Center for Study of Language and Information, Stanford.
4. Buszkowski, W.: 1989, ‘Presuppositional Completeness’, Studia Logica 48, 23–44.
5. Harrah, D.: 1984, ‘The Logic of Questions’, in: D. Gabbay and F. Guenthner (eds.), Handbook of Philosophical Logic. Volume II: Extensions of Classical Logic, D. Reidel, Dordrecht, pp. 715–764.