diff --git a/src/NodaUncertaintyHelper.php b/src/NodaUncertaintyHelper.php
index 50fd3eb..3726911 100644
--- a/src/NodaUncertaintyHelper.php
+++ b/src/NodaUncertaintyHelper.php
@@ -14,6 +14,8 @@ final class NodaUncertaintyHelper {
     const PERSINST_INDICATORS_DISALLOWED = [
         "Unbekannt",
         "unbekannt",
+        "Anonymus",
+        "Anonym",
         "n.n.",
         "N.N.",
         "Künstler, unbekannt",