Sudoku +...

I'm not sure if this is what the puzzle is called everywhere, but has anyone come across sudoku +?

I've seen it in magazines on the continent, and in sudoku plus basically there are numbers around the edge of the puzzle.

These tell you what the sum total of the first three cells in that region are, so for instance if you have a number 20 at the start of the row then you know the first three cells sum up to 20 (like 9,8,3 would be a possible combination).

I really enjoy this puzzle but can't seem to find it anywhere in the UK at all! I guess it's not something many people make.

Could I make a request to have a magazine of sudoku plus here, pleaaase? Thanks so much

Martha