the non-procedural variant of Transformational grammar (TG) of George Lakoff, that formulates constraints on potential tree sequences[3] Johnson and Postal's formalization of Relational grammar (RG) (1980), Generalized phrase structure grammar (GPSG) in the variants developed by Gazdar et al. (1988), Blackburn et al. (1993) and Rogers (1997)[3] Lexical functional grammar (LFG) in the formalization of Ronald Kaplan (1995)[3] Head-driven phrase structure grammar (HPSG) in the formalization of King (1999)[3] Constraint Handling Rules (CHR) grammars[4]