diff --git a/dmnverifierapi/src/main/java/de/unikoblenz/fgbks/base/utils/boundary/impl/StringBoundary.java b/dmnverifierapi/src/main/java/de/unikoblenz/fgbks/base/utils/boundary/impl/StringBoundary.java
index c0484570d89eab357a9a88bcd5b37e60b10c8433..5b5f311935170c2d77cfda113e333d0d9569c6f9 100644
--- a/dmnverifierapi/src/main/java/de/unikoblenz/fgbks/base/utils/boundary/impl/StringBoundary.java
+++ b/dmnverifierapi/src/main/java/de/unikoblenz/fgbks/base/utils/boundary/impl/StringBoundary.java
@@ -36,6 +36,7 @@ import de.unikoblenz.fgbks.base.utils.boundary.creater.CreaterUpper;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Objects;
+import java.util.stream.Collectors;
 import org.apache.commons.lang3.Validate;
 
 public class StringBoundary extends AbstractBoundary<String> {
@@ -147,6 +148,10 @@ public class StringBoundary extends AbstractBoundary<String> {
 
   @Override
   public String getParsedText() {
-    return (matchNoneOfValues ? "not" : "") + Arrays.toString(values);
+    return (matchNoneOfValues ? "not(" : "")
+        + Arrays.stream(values)
+        .map(v -> '"' + v + '"')
+        .collect(Collectors.joining(","))
+        + (matchNoneOfValues ? ")" : "");
   }
 }