Negative Modal Operators in Intuitionistic Logic Kosta Došen (1984) Publications de l'Institut Mathématique
Negative modal operators in intuitionistic logic. Došen, Kosta (1984) Publications de l'Institut Mathématique. Nouvelle Série
Normal forms in partial modal logic Jan Jaspars (1993) Banach Center Publications A "partial" generalization of Fine's definition [Fin] of normal forms in normal minimal modal logic is given. This means quick access to complete axiomatizations and decidability proofs for partial modal logic [Thi].