diff --git a/src/main/java/org/gcube/accounting/aggregation/ServiceUsageRecord.java b/src/main/java/org/gcube/accounting/aggregation/ServiceUsageRecord.java
index f65e6a9..9807e97 100644
--- a/src/main/java/org/gcube/accounting/aggregation/ServiceUsageRecord.java
+++ b/src/main/java/org/gcube/accounting/aggregation/ServiceUsageRecord.java
@@ -29,9 +29,9 @@ public class ServiceUsageRecord extends org.gcube.accounting.datamodel.basetypes
 	public static final String DURATION = org.gcube.accounting.datamodel.basetypes.ServiceUsageRecord.DURATION;
 	
 	@RequiredField @ValidLong @AggregatedField
-	protected static final String MAX_INVOCATION_TIME = "maxInvocationTime";
+	public static final String MAX_INVOCATION_TIME = "maxInvocationTime";
 	@RequiredField @ValidLong @AggregatedField
-	protected static final String MIN_INVOCATION_TIME = "minInvocationTime";
+	public static final String MIN_INVOCATION_TIME = "minInvocationTime";
 	
 	private void init(){
 		this.resourceProperties.put(AGGREGATED, true);
diff --git a/src/main/java/org/gcube/accounting/datamodel/AggregatedUsageRecord.java b/src/main/java/org/gcube/accounting/datamodel/AggregatedUsageRecord.java
index f3a49a3..b064cb3 100644
--- a/src/main/java/org/gcube/accounting/datamodel/AggregatedUsageRecord.java
+++ b/src/main/java/org/gcube/accounting/datamodel/AggregatedUsageRecord.java
@@ -3,6 +3,8 @@
  */
 package org.gcube.accounting.datamodel;
 
+import org.gcube.accounting.datamodel.decorators.AggregatedField;
+import org.gcube.accounting.datamodel.validations.annotations.ValidInteger;
 import org.gcube.accounting.exception.InvalidValueException;
 
 /**
@@ -10,6 +12,9 @@ import org.gcube.accounting.exception.InvalidValueException;
  */
 public interface AggregatedUsageRecord<T extends AggregatedUsageRecord<T, B>, B extends SingleUsageRecord> extends UsageRecord {
 	
+	@AggregatedField @ValidInteger
+	public static final String OPERATION_COUNT = "operationCount";
+	
 	public T getAggregatedUsageRecord(B usageRecord) throws InvalidValueException ;
 	
 }
diff --git a/src/main/java/org/gcube/accounting/datamodel/BasicUsageRecord.java b/src/main/java/org/gcube/accounting/datamodel/BasicUsageRecord.java
index 75a0485..8d4b753 100644
--- a/src/main/java/org/gcube/accounting/datamodel/BasicUsageRecord.java
+++ b/src/main/java/org/gcube/accounting/datamodel/BasicUsageRecord.java
@@ -123,6 +123,7 @@ public abstract class BasicUsageRecord implements UsageRecord, Serializable {
 	 */
 	@AggregatedField @NotEmptyIfNotNull
 	protected static final String AGGREGATED = "aggregated";
+	
 	/**
 	 * KEY for : Indicate The Number of Aggregated Operation 
 	 */
diff --git a/src/main/java/org/gcube/accounting/messaging/QueueCouple.java b/src/main/java/org/gcube/accounting/messaging/QueueCouple.java
index e0057bb..b75cb44 100644
--- a/src/main/java/org/gcube/accounting/messaging/QueueCouple.java
+++ b/src/main/java/org/gcube/accounting/messaging/QueueCouple.java
@@ -1,5 +1,8 @@
 package org.gcube.accounting.messaging;
 
+import org.gcube.accounting.aggregation.ServiceUsageRecord;
+
+
 @Deprecated
 public class QueueCouple {
 	
@@ -34,7 +37,5 @@ public class QueueCouple {
 	}
 	
 	
-	
-	
 
 }