diff --git a/src/NodaUncertaintyHelper.php b/src/NodaUncertaintyHelper.php
index 4cdc312..4464847 100644
--- a/src/NodaUncertaintyHelper.php
+++ b/src/NodaUncertaintyHelper.php
@@ -31,6 +31,9 @@ final class NodaUncertaintyHelper {
         "ismeretlen.",
         "Ismeretlen.",
         "ism.",
+        "невизначена", // "Uncertain" (ukr)
+        "невизначений", // "Unspecified" (ukr)
+        "не встановлено", // "Not established" (ukr)
     ];
 
     const PERSINST_UNCERTAINTY_PREFIXES = [