References
- Penttonen , M . 1974 . One-sided and two-sided context in formal grammars . Information and Control , 25 : 371 – 392 .
- Rozenberg G. Von Solms S. H. Priorities on context conditions in rewriting systems To appear in Information Sciences
- Van Der Walt , A.P.J . 1972 . Random context languages . Information Processing 71 , 1 : 66 – 68 .