Raymond P. Polivka. New problem: some diagonal fun. ACM SIGAPL APL Quote Quad, 35(4):27, 2007. [doi]
@article{Polivka07b, title = {New problem: some diagonal fun}, author = {Raymond P. Polivka}, year = {2007}, doi = {10.1145/1354923.1354928}, url = {http://doi.acm.org/10.1145/1354923.1354928}, researchr = {https://researchr.org/publication/Polivka07b}, cites = {0}, citedby = {0}, journal = {ACM SIGAPL APL Quote Quad}, volume = {35}, number = {4}, pages = {27}, }