Sudoku Puzzle Book for Adults: 3000 Very Hard to Extreme Hard Sudoku Puzzles with Solutions - Vol. 1: books, visupuzzle: 9798647700964: Amazon.com: Books
5 Step Sudoku I For Addicts Vol 3: 310 Puzzles! Easy, Medium, Hard, and Unfair Levels - Sudoku Puzzle Book (For Addicts I): Popps, John Joseph: 9781983724602: Amazon.com: Books
2021 Sudoku Daily Calendar: Sudoku Puzzles 9x9 Of The Year 2021 For Adults, 365 Puzzles, 5 Levels of Difficulty (Easy to Extreme): Bowers, Figueroa: 9798690969707: Amazon.com: Books