Killer Sudoku, Difficulty 7

Puzzle 5989 Sep 17 September 2012
Puzzle 6463 Dec 19 December 2012
Puzzle 6999 Apr 5 April 2013
Puzzle 7469 Jul 8 July 2013
Puzzle 7959 Oct 14 October 2013
Puzzle 7999 Oct 22 October 2013
Puzzle 8094 Nov 10 November 2013
Puzzle 8254 Dec 12 December 2013
Puzzle 8489 Jan 28 January 2014
Puzzle 8859 Apr 12 April 2014
Daily Killer Sudoku