Solomon W. Golomb, Kyle Calderhead. Orthogonal Sudoku Squares: 11214. The American Mathematical Monthly, 115(2):167-168, 2008. [doi]
@article{GolombC08, title = {Orthogonal Sudoku Squares: 11214}, author = {Solomon W. Golomb and Kyle Calderhead}, year = {2008}, url = {http://www.jstor.org/stable/27642432}, researchr = {https://researchr.org/publication/GolombC08}, cites = {0}, citedby = {0}, journal = {The American Mathematical Monthly}, volume = {115}, number = {2}, pages = {167-168}, }