394 books • 40 series
Variety Logic Puzzles - Jigsaw Sudoku, Killer Sudoku 200 Hard Puzzles 9x9 Book 19 (Variety Logic Puzzles, #19)
Variety Logic Puzzles - Jigsaw Sudoku, Killer Sudoku 200 Very Hard Puzzles 9x9 Book 20 (Variety Logic Puzzles, #20)
Skyscrapers Puzzles - 200 Easy to Very Hard Puzzles 9x9 Book 5 (Skyscrapers Puzzles, #5)