Challenging Sudoku Twelve Logic Puzzles (Vol 1) 
 Chapter 16: Two Challenging (DiffLev 19-20) tpsmith-serious Puzzles (numbers 111-112) 
 
-  Step-by-step instructions for solving  Puzzle 111, (99/144)   Diff: 19/964.4533.4376.5897.6232
 -  Step-by-step instructions for solving  Puzzle 112, (94/144)   Diff: 20/9644.2122.C245.5796.7482