My Best Mathematical and Logic Puzzles (Dover Recreational Math) (Dover Math Games & Puzzles) Gardner, Martin
The Ultimate Brain Health Puzzle Book for Adults: Engaging Word Games, Challenging Logic Puzzles, Relaxing Activities, and Brain-Boosting Fun for Focus and Mental Clarity Duane, G. Pitts
Will Shortz Presents Hard Sudoku Volume 8: 200 Challenging Puzzles (Will Shortz Presents, 8) Shortz, Will