Medium Sudoku Twelve Logic Puzzles (Vol 1) 
 Chapter 42: Two Medium (DiffLev 5-8) Productively Puzzles (numbers 163-164) 
 
-  Step-by-step instructions for solving  Puzzle 163, (74/144)   Diff: 5/9.9994
 -  Step-by-step instructions for solving  Puzzle 164, (88/144)   Diff: 8/9999.9962