Difficult Sudoku Twelve Logic Puzzles (Vol 1) 
 Chapter 16: Two Difficult (DiffLev 12-13) tpsmith-serious Puzzles (numbers 111-112) 
 
-  Step-by-step instructions for solving  Puzzle 111, (93/144)   Diff: 12/9956.3467.8993
 -  Step-by-step instructions for solving  Puzzle 112, (85/144)   Diff: 13/9.9793.5477.6593