diff --git a/model/forwarding-strategy/green-yellow-red.h b/model/forwarding-strategy/green-yellow-red.h
index 383f3f4..71002b9 100644
--- a/model/forwarding-strategy/green-yellow-red.h
+++ b/model/forwarding-strategy/green-yellow-red.h
@@ -42,7 +42,7 @@
 
   virtual bool
   DoPropagateInterest (const Ptr<CcnxFace> &incomingFace,
-                       Ptr<CcnxInterestHeader> &header,
+                       Ptr<CcnxInterestHeader> header,
                        const Ptr<const Packet> &packet,
                        Ptr<CcnxPitEntry> pitEntry);
   virtual void