Easy Sudoku Twelve Logic Puzzles (Vol 1) 
 Chapter 18: Two Easy (DiffLev 3-4) Backpointers Puzzles (numbers 115-116) 
 
-  Step-by-step instructions for solving  Puzzle 115, (51/144)   Diff: 3/994
 -  Step-by-step instructions for solving  Puzzle 116, (67/144)   Diff: 4/9998