Danièle Beauquier. An Undecidable Problem About Rational Sets and Contour Words of Polyominoes. Inf. Process. Lett., 37(5):257-263, 1991.
@article{Beauquier91, title = {An Undecidable Problem About Rational Sets and Contour Words of Polyominoes}, author = {Danièle Beauquier}, year = {1991}, researchr = {https://researchr.org/publication/Beauquier91}, cites = {0}, citedby = {0}, journal = {Inf. Process. Lett.}, volume = {37}, number = {5}, pages = {257-263}, }