1. Transductions and Context-Free Languages;Berstel,1979
2. String-Rewriting Systems;Book,1993
3. Semi-commutations and algebraic languages;Clerbout,1990
4. Open. Closed. Open;Dershowitz,2005
5. Decidability of termination of grid string rewriting rules;Geser;SIAM J. Comput.,2002