Variations on Advanced Sudoku Logic Puzzles (Vol 1) 
 Chapter 8: Two TournamentPlus Sudoku-12 Puzzles (numbers 19-20) 
 
-  Step-by-step instructions for solving  Puzzle 19, (91/144)   Diff: 34/52.3336.51B1.1322.1111.2312.2246.7222.2452
 -  Step-by-step instructions for solving  Puzzle 20, (98/144)   Diff: 41/3.1121.2211.111B.1A23.221C.2345.531A.2245+