diff --git a/src/main/java/org/gcube/accounting/analytics/persistence/AccountingPersistenceBackendQuery.java b/src/main/java/org/gcube/accounting/analytics/persistence/AccountingPersistenceBackendQuery.java
index 96bf4ca..047462b 100644
--- a/src/main/java/org/gcube/accounting/analytics/persistence/AccountingPersistenceBackendQuery.java
+++ b/src/main/java/org/gcube/accounting/analytics/persistence/AccountingPersistenceBackendQuery.java
@@ -96,7 +96,7 @@ public interface AccountingPersistenceBackendQuery {
 	 * @param clz
 	 * @param temporalConstraint
 	 * @param filters
-	 * @param topKey
+	 * @param key
 	 * @param orderingProperty
 	 * @return
 	 * @throws DuplicatedKeyFilterException
@@ -107,7 +107,7 @@ public interface AccountingPersistenceBackendQuery {
 	public SortedSet<NumberedFilter> getNextPossibleValues(
 			Class<? extends AggregatedRecord<?, ?>> clz,
 			TemporalConstraint temporalConstraint, List<Filter> filters,
-			String topKey, String orderingProperty) throws 
+			String key, String orderingProperty) throws 
 			DuplicatedKeyFilterException, KeyException, ValueException, 
 			Exception;
 
diff --git a/src/main/java/org/gcube/accounting/analytics/persistence/AccountingPersistenceQuery.java b/src/main/java/org/gcube/accounting/analytics/persistence/AccountingPersistenceQuery.java
index 156cb5e..59b3384 100644
--- a/src/main/java/org/gcube/accounting/analytics/persistence/AccountingPersistenceQuery.java
+++ b/src/main/java/org/gcube/accounting/analytics/persistence/AccountingPersistenceQuery.java
@@ -225,14 +225,14 @@ public class AccountingPersistenceQuery implements AccountingPersistenceBackendQ
 	public SortedSet<NumberedFilter> getNextPossibleValues(
 			Class<? extends AggregatedRecord<?,?>> clz,
 			TemporalConstraint temporalConstraint, List<Filter> filters,
-			String topKey) throws DuplicatedKeyFilterException, KeyException, 
+			String key) throws DuplicatedKeyFilterException, KeyException, 
 			ValueException, Exception {
 		
 		String orderingProperty = AccountingPersistenceQuery
 				.getDefaultOrderingProperties(clz);
 		
 		return this.getNextPossibleValues(clz, temporalConstraint, filters, 
-						topKey, orderingProperty);
+						key, orderingProperty);
 	}
 	
 	/**
@@ -242,13 +242,13 @@ public class AccountingPersistenceQuery implements AccountingPersistenceBackendQ
 	public SortedSet<NumberedFilter> getNextPossibleValues(
 			Class<? extends AggregatedRecord<?, ?>> clz,
 			TemporalConstraint temporalConstraint, List<Filter> filters,
-			String topKey, String orderingProperty) throws 
+			String key, String orderingProperty) throws 
 			DuplicatedKeyFilterException, KeyException, ValueException, 
 			Exception {
 		
 		return AccountingPersistenceBackendQueryFactory.getInstance()
 				.getNextPossibleValues(clz, temporalConstraint, filters, 
-						topKey, orderingProperty);
+						key, orderingProperty);
 		
 	}