1. Polish Logic;K. Ajdukiewicz,1967
2. —,A method of eliminating intensional sentences and sentential formulae,Atti del XII Congresso Internazionale di Filosofia (Venizia,12–18 Settembre 1958) Vol. 5, Florence, Sansoni Editore 1960, pp. 17–24.
3. J. C. Bigelow,Meaning and believing that (unpublished).
4. R. Carnap,Meaning and Necessity, Chicago, University of Chicago Press, 1947 (2nd ed. 1956).
5. M. J. Cresswell,Classical intensional logics,Theoria, Vol. 36 (1970), pp. 347–372.