Variations on Intermediate Sudoku Logic Puzzles (Vol 1) 
 Chapter 41: Eight Difficult Sudoku-8 Puzzles (numbers 229-236) 
 
-  Step-by-step instructions for solving  Puzzle 229, (40/64)   Diff: 9/8.5644.3622
 -  Step-by-step instructions for solving  Puzzle 230, (43/64)   Diff: 10/65.5552.5622
 -  Step-by-step instructions for solving  Puzzle 231, (44/64)   Diff: 10/95.3564.2343
 -  Step-by-step instructions for solving  Puzzle 232, (44/64)   Diff: 10/53.3648.5532
 -  Step-by-step instructions for solving  Puzzle 233, (40/64)   Diff: 11/664.2352.3432
 -  Step-by-step instructions for solving  Puzzle 234, (44/64)   Diff: 11/841.4353.4444
 -  Step-by-step instructions for solving  Puzzle 235, (44/64)   Diff: 11/534.5233.3691
 -  Step-by-step instructions for solving  Puzzle 236, (43/64)   Diff: 12/4114.6355.3452