Tobias Nipkow, Lawrence C. Paulson. Fun With Tilings. Archive of Formal Proofs, 2008, 2008. [doi]
@article{NipkowP08, title = {Fun With Tilings}, author = {Tobias Nipkow and Lawrence C. Paulson}, year = {2008}, url = {http://afp.sourceforge.net/entries/FunWithTilings.shtml}, note = {Formal proof development}, researchr = {https://researchr.org/publication/NipkowP08}, cites = {0}, citedby = {0}, journal = {Archive of Formal Proofs}, volume = {2008}, }