- SUDOKU PUZZLES: 501 Sudoku Puzzles for Advanced Solvers! 250 Very Hard, 250 Insane, 1 Inhuman! Volume 1
- Sudoku Puzzles for Advanced Solvers: 501 Sudoku Puzzles for Advanced Solvers! 250 Very Hard, 250 Insane, 1 Inhuman! Volume 3
- Sudoku Puzzles for Beginners: 501 Sudoku Puzzles for Beginner Solvers! 250 Easy, 250 Medium, 1 Hard! Volume 3
- Sudoku Puzzles for Beginners: 501 Sudoku Puzzles for Beginner Solvers! 250 Easy, 250 Medium, 1 Hard! Volume 2
- Sudoku Puzzles: 501 Sudoku Puzzles for Advanced Solvers! 250 Very Hard, 250 Insane, 1 Inhuman! Volume 2