Killer Sudoku, Difficulty 3

Puzzle 7568 Jul 28 July 2013
Puzzle 7578 Jul 30 July 2013
Puzzle 7593 Aug 2 August 2013
Puzzle 7603 Aug 4 August 2013
Puzzle 7613 Aug 6 August 2013
Puzzle 7623 Aug 8 August 2013
Puzzle 7633 Aug 10 August 2013
Puzzle 7643 Aug 12 August 2013
Puzzle 7653 Aug 14 August 2013
Puzzle 7663 Aug 16 August 2013
Daily Killer Sudoku