Green Brain Train Sudoku Book, 9x9 Puzzles, 150 Pages, 5x8, Medium

Green Brain Train Sudoku Book, 9x9 Puzzles, 150 Pages, 5x8, Easy

Blue Brain Train Sudoku Book, 9x9 Puzzles, 150 Pages, 5x8, Medium

Orange Brain Train Sudoku Book, 9x9 Puzzles, 150 Pages, 5x8, Medium

Green Brain Train Sudoku Book, 9x9 Puzzles, 150 Pages, 5x8, Hard