McGuire, G.; Tugemann, B.; Civario, G. (2014). "There is no 16-Clue Sudoku: Solving the Sudoku Minimum Number of Clues Problem". Experimental Mathematics. 23 (2): 190–217. arXiv:1201.0749. doi:10.1080/10586458.2013.870056.
McGuire, G.; Tugemann, B.; Civario, G. (2014). "There is no 16-Clue Sudoku: Solving the Sudoku Minimum Number of Clues Problem". Experimental Mathematics. 23 (2): 190–217. arXiv:1201.0749. doi:10.1080/10586458.2013.870056.