Medium Sudoku Eight Logic Puzzles (Vol 1) 
 Chapter 4: Sixteen Medium (DiffLev 7-8) Sudoku-8 Puzzles (numbers 15-30) 
 
-  Step-by-step instructions for solving  Puzzle 15, (39/64)   Diff: 7/964.5642
 -  Step-by-step instructions for solving  Puzzle 16, (39/64)   Diff: 7/545.7972
 -  Step-by-step instructions for solving  Puzzle 17, (40/64)   Diff: 7/565.8952
 -  Step-by-step instructions for solving  Puzzle 18, (41/64)   Diff: 7/866.7653
 -  Step-by-step instructions for solving  Puzzle 19, (42/64)   Diff: 7/944.8952
 -  Step-by-step instructions for solving  Puzzle 20, (43/64)   Diff: 7/766.9743
 -  Step-by-step instructions for solving  Puzzle 21, (37/64)   Diff: 8/9433.4662
 -  Step-by-step instructions for solving  Puzzle 22, (37/64)   Diff: 8/8445.3481
 -  Step-by-step instructions for solving  Puzzle 23, (38/64)   Diff: 8/6354.4754
 -  Step-by-step instructions for solving  Puzzle 24, (39/64)   Diff: 8/8513.2587
 -  Step-by-step instructions for solving  Puzzle 25, (40/64)   Diff: 8/7683.4651
 -  Step-by-step instructions for solving  Puzzle 26, (43/64)   Diff: 8/6762.6592
 -  Step-by-step instructions for solving  Puzzle 27, (43/64)   Diff: 8/5566.7653
 -  Step-by-step instructions for solving  Puzzle 28, (44/64)   Diff: 8/4467.6872
 -  Step-by-step instructions for solving  Puzzle 29, (45/64)   Diff: 8/9896.4522
 -  Step-by-step instructions for solving  Puzzle 30, (45/64)   Diff: 8/6558.7644