Variations on Intermediate Sudoku Logic Puzzles (Vol 1) 
 Chapter 20: Four Medium Sudoku-7B-X Puzzles (numbers 101-104) 
 
-  Step-by-step instructions for solving  Puzzle 101, (32/49)   Diff: 5/9.4791
 -  Step-by-step instructions for solving  Puzzle 102, (32/49)   Diff: 6/95.4462
 -  Step-by-step instructions for solving  Puzzle 103, (36/49)   Diff: 8/7544.2482
 -  Step-by-step instructions for solving  Puzzle 104, (40/49)   Diff: 8/2346.4495