Independently Published Killer Sudoku - 200 Hard to Master Puzzles 12x12 vol.18

Killer Sudoku is a mix of Sudoku and Kakuro. Your goal is the same as in regular sudoku: fill every row, column and 3x4 region with the numbers 1-12 once. The objective is to fill the grid with numbers from 1 to 12 in a way that the following conditions ar