diff --git a/dhp-schemas/src/main/java/eu/dnetlib/dhp/schema/dump/oaf/graph/GraphResult.java b/dhp-schemas/src/main/java/eu/dnetlib/dhp/schema/dump/oaf/graph/GraphResult.java
index 9b8fa0801..b4bee5a3b 100644
--- a/dhp-schemas/src/main/java/eu/dnetlib/dhp/schema/dump/oaf/graph/GraphResult.java
+++ b/dhp-schemas/src/main/java/eu/dnetlib/dhp/schema/dump/oaf/graph/GraphResult.java
@@ -1,4 +1,23 @@
 package eu.dnetlib.dhp.schema.dump.oaf.graph;
 
-public class GraphResult {
+import eu.dnetlib.dhp.schema.dump.oaf.Instance;
+import eu.dnetlib.dhp.schema.dump.oaf.Result;
+
+import java.util.List;
+
+/**
+ * It extends the eu.dnetlib.dhp.schema.dump.oaf.Result with
+ * - instance of type List<eu.dnetlib.dhp.schema.dump.oaf.Instance> to store all the instances associated
+ *   to the result. It corresponds to the same parameter in the result represented in the internal model
+ */
+public class GraphResult extends Result {
+    private List<Instance> instance;
+
+    public List<Instance> getInstance() {
+        return instance;
+    }
+
+    public void setInstance(List<Instance> instance) {
+        this.instance = instance;
+    }
 }