Easy Sudoku Twelve Logic Puzzles (Vol 1) 
 Chapter 30: Two Easy (DiffLev 3-4) Headstrongly Puzzles (numbers 139-140) 
 
-  Step-by-step instructions for solving  Puzzle 139, (48/144)   Diff: 3/992
 -  Step-by-step instructions for solving  Puzzle 140, (68/144)   Diff: 4/9993