(2012). Sudoku: Over 400 challenging sudoku puzzles. Parragon.
Chicago Style (17th ed.) CitationSudoku: Over 400 Challenging Sudoku Puzzles. Bath: Parragon, 2012.
MLA (9th ed.) CitationSudoku: Over 400 Challenging Sudoku Puzzles. Parragon, 2012.
Warning: These citations may not always be 100% accurate.