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

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

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

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

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