Book of Sudoku Variants - Suguru, Futoshiki, Binary, Numbricks, CalcuDoku - 200 Hard Puzzles Book 4 Paperback $7.99
Book of Sudoku Variants - Jigsaw Sudoku, Killer Sudoku, Tripod Sudoku, Sudoku X - 200 Hard Puzzles Book 2 Paperback $7.99