The Big Book of Jigsaw Sudoku: 400 Jigsaw Sudoku Puzzles: Williams, Dewi: 9781499225044: Amazon.com: Books
Jigsaw Sudoku Puzzle Book for Adults: Irregular Sudoku Japanese Math Logic Puzzles | Easy to Hard | 156 Puzzles: Publishing, Puzzle King: 9798675538249: Amazon.com: Books