diff --git a/cpp/Conditional.h b/cpp/Conditional.h
index dba0a68d0..601c30d2c 100644
--- a/cpp/Conditional.h
+++ b/cpp/Conditional.h
@@ -9,57 +9,71 @@
 #pragma once
 
 #include <boost/utility.hpp> // for noncopyable
+#include <boost/serialization/string.hpp>
 #include "Testable.h"
 
 namespace gtsam {
 
-  /** 
-   * Base class for conditional densities
-   *
-   * We make it noncopyable so we enforce the fact that factors are
-   * kept in pointer containers. To be safe, you should make them
-   * immutable, i.e., practicing functional programming.
-   */ 
-  class Conditional : boost::noncopyable, public Testable<Conditional>
-  {
-  protected:
+/**
+ * Base class for conditional densities
+ *
+ * We make it noncopyable so we enforce the fact that factors are
+ * kept in pointer containers. To be safe, you should make them
+ * immutable, i.e., practicing functional programming.
+ */
+class Conditional: boost::noncopyable, public Testable<Conditional> {
+protected:
 
-  	/** key of random variable */
-  	std::string key_;
+	/** key of random variable */
+	std::string key_;
 
-  public:
+public:
 
-  	/** constructor */
-  	Conditional(const std::string& key):key_(key) {}
+	/** constructor */
+	Conditional(const std::string& key) :
+		key_(key) {
+	}
 
-  	/* destructor */
-    virtual ~Conditional() {};
+	/* destructor */
+	virtual ~Conditional() {
+	}
+	;
 
-		/** check equality */
-		bool equals(const Conditional& c, double tol = 1e-9) const {
-			return key_ == c.key_;
-		}
+	/** check equality */
+	bool equals(const Conditional& c, double tol = 1e-9) const {
+		return key_ == c.key_;
+	}
 
-		/** return key */
-    inline const std::string& key() const { return key_;}
-		
-    /** return parent keys */
-    virtual std::list<std::string> parents() const = 0;
-		
-    /** return the number of parents */
-    virtual std::size_t nrParents() const = 0;
-  };
+	/** return key */
+	inline const std::string& key() const {
+		return key_;
+	}
 
-	// predicate to check whether a conditional has the sought key
-	template<class Conditional>
-	class onKey {
-		const std::string& key_;
-	public:
-		onKey(const std::string& key):key_(key) {}
-		bool operator()(const typename Conditional::shared_ptr& conditional) {
-			return (conditional->key()==key_);
-		}
-	};
+	/** return parent keys */
+	virtual std::list<std::string> parents() const = 0;
 
+	/** return the number of parents */
+	virtual std::size_t nrParents() const = 0;
 
+private:
+	/** Serialization function */
+	friend class boost::serialization::access;
+	template<class Archive>
+	void serialize(Archive & ar, const unsigned int version) {
+		ar & BOOST_SERIALIZATION_NVP(key_);
+	}
+};
+
+// predicate to check whether a conditional has the sought key
+template<class Conditional>
+class onKey {
+	const std::string& key_;
+public:
+	onKey(const std::string& key) :
+		key_(key) {
+	}
+	bool operator()(const typename Conditional::shared_ptr& conditional) {
+		return (conditional->key() == key_);
+	}
+};
 }
diff --git a/cpp/ConditionalGaussian.h b/cpp/ConditionalGaussian.h
index 2e3b941c8..2e424b36a 100644
--- a/cpp/ConditionalGaussian.h
+++ b/cpp/ConditionalGaussian.h
@@ -13,7 +13,6 @@
 #include <boost/utility.hpp>
 #include <boost/shared_ptr.hpp>
 #include <boost/serialization/map.hpp>
-#include <boost/serialization/string.hpp>
 #include <boost/serialization/shared_ptr.hpp>
 
 #include "Conditional.h"
@@ -44,12 +43,12 @@ protected:
 	/** the names and the matrices connecting to parent nodes */
 	Parents parents_;
 
-	/** vector of standard deviations */
-	Vector sigmas_;
-
 	/** the RHS vector */
 	Vector d_;
 
+	/** vector of standard deviations */
+	Vector sigmas_;
+
 public:
 
 	/** default constructor needed for serialization */
@@ -141,10 +140,11 @@ private:
 	friend class boost::serialization::access;
 	template<class Archive>
 	void serialize(Archive & ar, const unsigned int version) {
+		ar & boost::serialization::make_nvp("Conditional", boost::serialization::base_object<Conditional>(*this));
 		ar & BOOST_SERIALIZATION_NVP(R_);
+		ar & BOOST_SERIALIZATION_NVP(parents_);
 		ar & BOOST_SERIALIZATION_NVP(d_);
 		ar & BOOST_SERIALIZATION_NVP(sigmas_);
-		ar & BOOST_SERIALIZATION_NVP(parents_);
 	}
 };
 }
diff --git a/cpp/SymbolicConditional.h b/cpp/SymbolicConditional.h
index 8dd97f19f..adf6087d3 100644
--- a/cpp/SymbolicConditional.h
+++ b/cpp/SymbolicConditional.h
@@ -13,6 +13,7 @@
 #include <iostream>
 #include <boost/shared_ptr.hpp>
 #include <boost/foreach.hpp> // TODO: make cpp file
+#include <boost/serialization/list.hpp>
 #include "Conditional.h"
 
 namespace gtsam {
@@ -88,6 +89,13 @@ namespace gtsam {
 			return parents_.size();
 		}
 
+	private:
+		/** Serialization function */
+		friend class boost::serialization::access;
+		template<class Archive>
+		void serialize(Archive & ar, const unsigned int version) {
+			ar & boost::serialization::make_nvp("Conditional", boost::serialization::base_object<Conditional>(*this));
+			ar & BOOST_SERIALIZATION_NVP(parents_);
+		}
 	};
-
 } /// namespace gtsam