Stephen Lubin
160 All Hard Level Pocket Sudoku Puzzle Book- 160 All Medium Level Pocket Sudoku Puzzle Book
- 500 Sudoku Puzzles Book for Adult Vol. 2
- 500 Sudoku Puzzles Book for Adult Vol. 3
- 500 Sudoku Puzzles Book for Adult Vol. 5
- All Hard SUDOKU for Adults 500 Puzzles Books Vol. 1
- All Hard SUDOKU for Adults 500 Puzzles Books Vol. 2
- All Hard SUDOKU for Adults 500 Puzzles Books Vol. 3
- All Hard SUDOKU for Adults 500 Puzzles Books Vol. 4
- All Hard SUDOKU for Adults 500 Puzzles Books Vol. 5