9 books
Jumbo Sudoku Puzzle Book For Adults (Vol. 1)
Compact Size SUDOKU Puzzle Book For Adults
BEGINNER Sudoku Puzzle Book For Adults
Hard Sudoku Puzzle Book for Adults
MEDIUM Sudoku Puzzle Book For Adults
Sudoku Puzzle Book for Smart Kids
Easy Sudoku Puzzle Book For Adults
Beginner Sudoku
Easy to Medium Sudoku Puzzle Book for Adults