diff --git a/model/forwarding-strategy/smart-flooding.h b/model/forwarding-strategy/smart-flooding.h
index 3e1cca6..840ce6a 100644
--- a/model/forwarding-strategy/smart-flooding.h
+++ b/model/forwarding-strategy/smart-flooding.h
@@ -43,7 +43,7 @@
   // inherited
   virtual bool
   DoPropagateInterest (const Ptr<CcnxFace> &incomingFace,
-                       Ptr<CcnxInterestHeader> &header,
+                       Ptr<CcnxInterestHeader> header,
                        const Ptr<const Packet> &packet,
                        Ptr<CcnxPitEntry> pitEntry);