Challenging Sudoku Twelve Logic Puzzles (Vol 1) 
 Chapter 54: Two Challenging (DiffLev 15-18) Unpredicably Puzzles (numbers 187-188) 
 
-  Step-by-step instructions for solving  Puzzle 187, (89/144)   Diff: 15/954.4342.2489.5998
 -  Step-by-step instructions for solving  Puzzle 188, (96/144)   Diff: 18/75.4769.4432.6648.4683