1. Lennart Åqvist, A New Approach to the Logical Theory of Interrogatives, Part I: Analysis, Uppsala 1965.
2. Lennart Åqvist, The Harrah review is in the Journal of Symbolic Logic
32 (1967) 403–404. My own work is represented by An Analysis of Questions: Preliminary Report, System Development Corporation, Santa Monica, 1963.
3. Lennart Åqvist, ‘Scattered Topics in Interrogative Logic’, in the present volume, p. 114.
4. Help from Ernest Sosa came from conversations and from his 1963 University of Pittsburgh doctoral dissertation, Formalization of the Logic of Imperatives, while the influence from Rescher was via both numerous conversations and his book The Logic of Commands, London 1966.
5. This research was supported by the System Development Corporation, Santa Monica. The ideas were worked out with Thomas Steel, and much clarified by conversations with David Harrah.