Logic Masters Deutschland e.V.

SudokuPad link (via tinyURL)
F-puzzles link

Normal Sudoku rules apply. Place the digits 1 through 9 in each empty cell. Digits must not repeat within the same row, column, or box.
The digits along each arrow must sum to the digit in the circled cell. Digits may repeat along an arrow if permitted by other rules.
A black dot between cells indicates cell values with a 2:1 ratio. A white dot between cells indicates cells with consecutive values. Not all dots are shown.