1. An undecidable problem about rational sets and contour words of polyominoes;Beauquier;Inform. Process. Lett.,1991
2. Tiling the plane with one tile, Proceedings of the Sixth Annual Symposium on Computer Geometry;Beauquier,1990
3. The undecidability of the domino problem;Berger;Memoirs Amer. Math. Soc.,1966
4. On the encoding of arbitrary geometric configurations;Freeman;IRE Trans.,1961
5. Computers and Intractability;Garey,1979