394 books • 40 series
Non-Consecutive Sudoku - 200 Hard to Very Hard Puzzles 9x9 vol.7 (Non-Consecutive Sudoku, #7)
Non-Consecutive Sudoku - 200 Easy to Very Hard Puzzles 9x9 vol.8 (Non-Consecutive Sudoku, #8)
Non-Consecutive Sudoku - 200 Normal to Hard Puzzles 9x9 vol.6 (Non-Consecutive Sudoku, #6)