Killer Sudoku, Difficulty 3

Puzzle 3391 May 4 May 2011
Puzzle 3396 May 5 May 2011
Puzzle 3401 May 6 May 2011
Puzzle 3406 May 7 May 2011
Puzzle 3411 May 8 May 2011
Puzzle 3416 May 9 May 2011
Puzzle 3421 May 10 May 2011
Puzzle 3426 May 11 May 2011
Puzzle 3431 May 12 May 2011
Puzzle 3436 May 13 May 2011
Daily Killer Sudoku