diff --git a/dnet-ariadneplus-graphdb-publisher/src/main/resources/eu/dnetlib/ariadneplus/sparql/enrich/NIAM/ordered_sparql_insert_niam.sparql b/dnet-ariadneplus-graphdb-publisher/src/main/resources/eu/dnetlib/ariadneplus/sparql/enrich/NIAM/ordered_sparql_insert_niam.sparql
index 8cd7bef..2383841 100644
--- a/dnet-ariadneplus-graphdb-publisher/src/main/resources/eu/dnetlib/ariadneplus/sparql/enrich/NIAM/ordered_sparql_insert_niam.sparql
+++ b/dnet-ariadneplus-graphdb-publisher/src/main/resources/eu/dnetlib/ariadneplus/sparql/enrich/NIAM/ordered_sparql_insert_niam.sparql
@@ -128,14 +128,17 @@ INSERT {
  }
  WHERE {
  	GRAPH <https://ariadne-infrastructure.eu/api_________::ariadne_plus::niam::amb> {
-       ?temporal aocat:has_native_period ?native_period .
-        ?native_period skos:prefLabel ?native_label .
-        optional {
-            GRAPH <https://ariadne-infrastructure.eu/ariadneplus::niam::periodo> {
-                ?periodO skos:altLabel ?native_label .
-                ?periodO time:intervalStartedBy / time:hasDateTimeDescription / time:year ?temporalFrom .
-                ?periodO time:intervalFinishedBy / time:hasDateTimeDescription / time:year ?temporalUntil .
-            }
+           ?temporal aocat:has_native_period ?native_period .
+            ?native_period skos:prefLabel ?t_label .
+            optional {
+                GRAPH <https://ariadne-infrastructure.eu/ariadneplus::niam::periodo> {
+                    ?periodO skos:altLabel ?p_label .
+                    ?periodO time:intervalStartedBy / time:hasDateTimeDescription / time:year ?temporalFrom .
+                    ?periodO time:intervalFinishedBy / time:hasDateTimeDescription / time:year ?temporalUntil .
+                }
+           }
+            bind(ucase(?t_label) as ?u_t_label)
+            bind(ucase(?p_label) as ?u_p_label)
+            filter(?u_t_label=?u_p_label)
        }
-   }
  };