Roger Villemaire. The Theory of (N, +, Vk, V1) is Undecidable. Theoretical Computer Science, 106(2):337-349, 1992.
@article{Villemaire92:1, title = {The Theory of (N, +, Vk, V1) is Undecidable}, author = {Roger Villemaire}, year = {1992}, researchr = {https://researchr.org/publication/Villemaire92%3A1}, cites = {0}, citedby = {0}, journal = {Theoretical Computer Science}, volume = {106}, number = {2}, pages = {337-349}, }