diff --git a/gtsam/inference/BayesNet-inl.h b/gtsam/inference/BayesNet-inl.h
index c306cb39d..912e49ef4 100644
--- a/gtsam/inference/BayesNet-inl.h
+++ b/gtsam/inference/BayesNet-inl.h
@@ -112,14 +112,14 @@ namespace gtsam {
 
   /* ************************************************************************* */
   template<class CONDITIONAL>
-  void BayesNet<CONDITIONAL>::push_back(const BayesNet<CONDITIONAL> bn) {
+  void BayesNet<CONDITIONAL>::push_back(const BayesNet<CONDITIONAL>& bn) {
     BOOST_FOREACH(sharedConditional conditional,bn.conditionals_)
       push_back(conditional);
   }
 
   /* ************************************************************************* */
   template<class CONDITIONAL>
-  void BayesNet<CONDITIONAL>::push_front(const BayesNet<CONDITIONAL> bn) {
+  void BayesNet<CONDITIONAL>::push_front(const BayesNet<CONDITIONAL>& bn) {
     BOOST_FOREACH(sharedConditional conditional,bn.conditionals_)
       push_front(conditional);
   }
diff --git a/gtsam/inference/BayesNet.h b/gtsam/inference/BayesNet.h
index 67d59c48d..4fa10eee2 100644
--- a/gtsam/inference/BayesNet.h
+++ b/gtsam/inference/BayesNet.h
@@ -93,9 +93,6 @@ public:
   void print(const std::string& s = "",
   		const IndexFormatter& formatter = DefaultIndexFormatter) const;
 
-  /** print statistics */
-  void printStats(const std::string& s = "") const;
-
   /** check equality */
   bool equals(const BayesNet& other, double tol = 1e-9) const;
 
@@ -108,6 +105,9 @@ public:
     return conditionals_.size();
   }
 
+  /** print statistics */
+  void printStats(const std::string& s = "") const;
+
   /** return keys in reverse topological sort order, i.e., elimination order */
   FastList<Index> ordering() const;
 
@@ -190,10 +190,10 @@ public:
   }
 
   /// push_back an entire Bayes net
-  void push_back(const BayesNet<CONDITIONAL> bn);
+  void push_back(const BayesNet<CONDITIONAL>& bn);
 
   /// push_front an entire Bayes net
-  void push_front(const BayesNet<CONDITIONAL> bn);
+  void push_front(const BayesNet<CONDITIONAL>& bn);
 
   /** += syntax for push_back, e.g. bayesNet += c1, c2, c3
    * @param conditional The conditional to add to the back of the BayesNet