Variations on Advanced Sudoku Logic Puzzles (Vol 1) 
 Chapter 52: Four Medium HyperSudoku-16 Puzzles (numbers 173-176) 
 
-  Step-by-step instructions for solving  Puzzle 173, (126/256)   Diff: 7/999.9543
 -  Step-by-step instructions for solving  Puzzle 174, (129/256)   Diff: 7/999.9942
 -  Step-by-step instructions for solving  Puzzle 175, (134/256)   Diff: 8/9999.9993
 -  Step-by-step instructions for solving  Puzzle 176, (137/256)   Diff: 8/9999.9951