Will Shortz Presents Hard Sudoku Volume 2: 200 Challenging Puzzles (Hard Sudoku, 2)

Will Shortz Presents Hard Sudoku Volume 3: 200 Challenging Puzzles

Will Shortz Presents Hard Sudoku Volume 1: 200 Challenging Puzzles

Will Shortz Presents Survival of the Fittest Sudoku: 200 Hard Puzzles

Will Shortz Presents Hard Sudoku Volume 5: 200 Challenging Puzzles

Will Shortz Presents The Huge Book of Hard Sudoku: 300 Challenging Puzzles

Will Shortz Presents Surrender to Sudoku: 200 Irresistibly Hard Puzzles

Will Shortz Presents Perfectly Impossible Sudoku: 200 Very Hard Puzzles

Will Shortz Presents Terrifying Sudoku

500+ Hard Sudoku Puzzles for Adults: Sudoku Puzzle Books Hard (with answers)

Will Shortz Presents Extra Hot Sudoku: 200 Hard Puzzles: Hard Sudoku Volume 1