Frank Longo - Böcker

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Blockbuster Book of Sudoku

Absolutely Nasty® Sudoku Level 3

Way Beyond Black Belt Sudoku (R)

The New York Times on the Web Crosswords for Teens

Fertilization

Second-Degree Green Belt Sudoku®

Second-Degree Brown Belt Sudoku®

Second-Degree Black Belt Sudoku®

Absolutely Nasty® Sudoku Level 1

Absolutely Nasty® Sudoku Level 2

Absolutely Nasty® Sudoku Level 4

Third-Degree White Belt Sudoku®

Third-Degree Brown Belt Sudoku®

Third-Degree Black Belt Sudoku®

Nastiest Sudoku Book Ever

Beyond Black Belt Sudoku

If you have to ask, it's too hard for you.

Poolside Sudoku

mental_floss Sudoku

It's the Brain Candy You've Been Craving!

Puzzlewright Guide to Solving Sudoku

Hundreds of Puzzles Plus Techniques to Help You Crack Them All

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Great Book of Sudoku

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Skill Builder Sudoku: Easy to Medium