Jigsaw Sudoku: 250 Medium Jigsaw Sudoku Puzzles (Irregularly Shaped Sudoku) (en Inglés)

Reseña del libro

Also the puzzle may contain the regions of random (irregular) shape; this variant is called Jigsaw Sudoku ("Geometry Sudoku", "Geometry Number Place", "Irregular Sudoku", "Kikagaku Nanpure").