520 books • 20 series
Killer Sudoku - Hermit - X Diagonal 10 X 10 - 250 Puzzles - Level Gold (10 X 10 Pitstop, #18)
Killer Sudoku - Anti - Knight - X Diagonal 10 X 10 - 250 Puzzles - Level Silver (10 X 10 Pitstop, #14)
Killer Sudoku - Anti-Knight - X Diagonal. 10 X 10. 250 Puzzles - Level Gold (10 X 10 Pitstop, #15)
Killer Sudoku - Hermit - X Diagonal - 10 X 10 - 250 Puzzles - Level Bronze (10 X 10 Pitstop, #16)