diff --git a/codego/aussagenlogik/recursion/recursion_nnf.go b/codego/aussagenlogik/recursion/recursion_nnf.go
index d613fd5..73acd42 100644
--- a/codego/aussagenlogik/recursion/recursion_nnf.go
+++ b/codego/aussagenlogik/recursion/recursion_nnf.go
@@ -64,9 +64,20 @@ func NNF(fml formulae.Formula) formulae.Formula {
 			}
 		} else if fml.IsImplication() {
 			return formulae.FormulaPair{
-				Pos: formulae.Implies(prevPos[0], prevPos[1]),
+				Pos: formulae.Disjunction2(prevNeg[0], prevPos[1]),
 				Neg: formulae.Conjunction2(prevPos[0], prevNeg[1]),
 			}
+		} else if fml.IsDoubleImplication() {
+			return formulae.FormulaPair{
+				Pos: formulae.Conjunction2(
+					formulae.Disjunction2(prevNeg[0], prevPos[1]),
+					formulae.Disjunction2(prevNeg[1], prevPos[0]),
+				),
+				Neg: formulae.Disjunction2(
+					formulae.Conjunction2(prevPos[0], prevNeg[1]),
+					formulae.Conjunction2(prevPos[1], prevNeg[0]),
+				),
+			}
 		} else {
 			panic("Could not evaluate expression!")
 		}