Tournament Sudoku Twelve Logic Puzzles (Vol 1) 
 Chapter 4: Twelve Tournament (DiffLev 26-29) Sudoku-12 Puzzles (numbers 13-24) 
 
-  Step-by-step instructions for solving  Puzzle 13, (90/144)   Diff: 26/73.4242.D122.1132.6645.5233.3375
 -  Step-by-step instructions for solving  Puzzle 14, (91/144)   Diff: 28/9452.432C.42A2.2111.1124.2259.7345
 -  Step-by-step instructions for solving  Puzzle 15, (94/144)   Diff: 28/973B.B312.3111.2121.A223.7444.8934
 -  Step-by-step instructions for solving  Puzzle 16, (94/144)   Diff: 28/941B.1A1A.B21A.1331.1B47.5434.5898
 -  Step-by-step instructions for solving  Puzzle 17, (96/144)   Diff: 28/9632.2133.2212.1122.1C23.2248.7697
 -  Step-by-step instructions for solving  Puzzle 18, (96/144)   Diff: 28/6522.2432.2321.1C22.3233.5357.8762
 -  Step-by-step instructions for solving  Puzzle 19, (92/144)   Diff: 29/6.5221.BAA2.3235.5632.2113.3263.4853
 -  Step-by-step instructions for solving  Puzzle 20, (95/144)   Diff: 29/9.8723.2431.1223.1124.1B24.5522.4444
 -  Step-by-step instructions for solving  Puzzle 21, (95/144)   Diff: 29/9.6B11.2211.4244.421B.1133.2525.7836
 -  Step-by-step instructions for solving  Puzzle 22, (95/144)   Diff: 29/5.2111.2123.1B11.21C2.4589.4357.3259
 -  Step-by-step instructions for solving  Puzzle 23, (96/144)   Diff: 29/8.661A.A1A2.2563.221A.1446.3334.3646
 -  Step-by-step instructions for solving  Puzzle 24, (96/144)   Diff: 29/7.7212.2223.2B1A.2447.6113.4556.4442