Group Puzzles (Sudoku Generalized) Challenging Sudoku Logic Puzzles, Volume 1.
  1. Teaching Logic using Group Puzzles
  2. Solving Group Logic Puzzles
  3. Thirty Challenging (DiffLev 15) Sudoku Puzzles (numbers 1-30)
  4. Thirty Challenging (DiffLev 16) Sudoku Puzzles (numbers 31-60)
  5. Thirty Challenging (DiffLev 17) Sudoku Puzzles (numbers 61-90)
  6. Thirty Challenging (DiffLev 18) Sudoku Puzzles (numbers 91-120)
  7. Thirty Challenging (DiffLev 19) Sudoku Puzzles (numbers 121-150)
  8. Thirty Challenging (DiffLev 20) Sudoku Puzzles (numbers 151-180)