Medium Sudoku Seven Logic Puzzles (Vol 1) 
 Chapter 4: Fourteen Medium (DiffLev 7-8) Sudoku-7 Puzzles (numbers 15-28) 
 
-  Step-by-step instructions for solving  Puzzle 15, (35/49)   Diff: 7/946.4642
 -  Step-by-step instructions for solving  Puzzle 16, (37/49)   Diff: 7/244.7991
 -  Step-by-step instructions for solving  Puzzle 17, (37/49)   Diff: 7/236.8882
 -  Step-by-step instructions for solving  Puzzle 18, (38/49)   Diff: 7/423.5798
 -  Step-by-step instructions for solving  Puzzle 19, (39/49)   Diff: 7/846.6951
 -  Step-by-step instructions for solving  Puzzle 20, (34/49)   Diff: 8/6344.6632
 -  Step-by-step instructions for solving  Puzzle 21, (35/49)   Diff: 8/7432.3592
 -  Step-by-step instructions for solving  Puzzle 22, (35/49)   Diff: 8/5434.2683
 -  Step-by-step instructions for solving  Puzzle 23, (36/49)   Diff: 8/5551.2486
 -  Step-by-step instructions for solving  Puzzle 24, (37/49)   Diff: 8/4324.6891
 -  Step-by-step instructions for solving  Puzzle 25, (38/49)   Diff: 8/6454.2665
 -  Step-by-step instructions for solving  Puzzle 26, (40/49)   Diff: 8/5647.5661
 -  Step-by-step instructions for solving  Puzzle 27, (40/49)   Diff: 8/4453.4866
 -  Step-by-step instructions for solving  Puzzle 28, (40/49)   Diff: 8/3543.7585