Variations on Sudoku-by5 Logic Puzzles (Vol 1) 
 Chapter 32: Three Medium HyperSudoku-Xtreme Puzzles (numbers 88-90) 
 
-  Step-by-step instructions for solving  Puzzle 88, (239/369)   Diff: 6/99.9995
 -  Step-by-step instructions for solving  Puzzle 89, (222/369)   Diff: 7/999.9432
 -  Step-by-step instructions for solving  Puzzle 90, (230/369)   Diff: 7/999.9972