1. Projective and supercoherent frames;Banaschewski;J. Pure Appl. Algebra,1991
2. Relative and modified relative realizability;Birkedal;Ann. Pure Appl. Log.,2002
3. Some free constructions in realizability and proof theory;Carboni;J. Pure Appl. Algebra,1995
4. A categorical approach to realizability and polymorphic types;Carboni,1988