diff --git a/Sudoku/SudokuEvent.mch b/Sudoku/SudokuEvent.mch
index a582d652527b115b07c2abd6a897d031c1b737c0..27283a958d4f1f4370a814acfd2f7d56712b204f 100644
--- a/Sudoku/SudokuEvent.mch
+++ b/Sudoku/SudokuEvent.mch
@@ -1,6 +1,7 @@
 MACHINE SudokuEvent
 /* A version of Sudoku where the solving happens inside an event
- (c) Michael Leuschel
+ (c) 2021 Michael Leuschel
+ VisB Visualisation by Matteo Röhle and Michael Leuschel
 */
 DEFINITIONS
  Sze == 3; Mx==(Sze*Sze);