Propositional quantifiers in modal logic1

[1]  R. A. Bull.  On Modal Logic with Propositional Quantifiers , 1969, J. Symb. Log..

[2]  K. Segerberg.  Decidability of S4.1 , 2008 .

[3]  Max J. Cresswell,et al.  A Henkin completeness for T , 1967, Notre Dame J. Formal Log..

[4]  Saul Kripke,et al.  A completeness theorem in modal logic , 1959, Journal of Symbolic Logic.