Matthias Jantzen and Manfred Kudlek.
Homomorphic images of sentential form languages defined by
semi-Thue systems.
Theoretical Computer Science, 33:13-43, 1984.
@article{Jantzen+84c, Author = {Jantzen, Matthias and Kudlek, Manfred}, Journal = TCS, Pages = {13--43}, Title = {Homomorphic images of sentential form languages defined by semi-{Thue} systems}, Volume = 33, Year = 1984 }