Paliath Narendran, Robert McNaughton. The Undecidability of the Preperfectness of Thue Systems. Theoretical Computer Science, 31:165-174, 1984.
@article{NarendranM84, title = {The Undecidability of the Preperfectness of Thue Systems}, author = {Paliath Narendran and Robert McNaughton}, year = {1984}, researchr = {https://researchr.org/publication/NarendranM84}, cites = {0}, citedby = {0}, journal = {Theoretical Computer Science}, volume = {31}, pages = {165-174}, }