diff --git a/Cantera/src/thermo/Elements.cpp b/Cantera/src/thermo/Elements.cpp
index 945654dfd..0e862bed6 100644
--- a/Cantera/src/thermo/Elements.cpp
+++ b/Cantera/src/thermo/Elements.cpp
@@ -34,6 +34,7 @@ using namespace std;
 #ifdef USE_DGG_CODE
 #include <map>
 #endif
+#include <cstdlib>
 
 namespace Cantera {
 
diff --git a/Cantera/src/thermo/PDSS_HKFT.cpp b/Cantera/src/thermo/PDSS_HKFT.cpp
index ad9a42218..313e140d3 100644
--- a/Cantera/src/thermo/PDSS_HKFT.cpp
+++ b/Cantera/src/thermo/PDSS_HKFT.cpp
@@ -21,6 +21,8 @@
 #include "WaterProps.h"
 #include "PDSS_Water.h"
 
+#include <cstdlib>
+
 using namespace std;
 
 namespace Cantera {
diff --git a/Cantera/src/thermo/PureFluidPhase.cpp b/Cantera/src/thermo/PureFluidPhase.cpp
index 80034d987..a0748e18c 100644
--- a/Cantera/src/thermo/PureFluidPhase.cpp
+++ b/Cantera/src/thermo/PureFluidPhase.cpp
@@ -16,6 +16,8 @@
 #include "../../../ext/tpx/Sub.h"
 #include "../../../ext/tpx/utils.h"
 
+#include <cstdlib>
+
 namespace Cantera {
 
   // Base Constructor
diff --git a/Cantera/src/thermo/ThermoFactory.cpp b/Cantera/src/thermo/ThermoFactory.cpp
index 48d6e1191..5940a580a 100644
--- a/Cantera/src/thermo/ThermoFactory.cpp
+++ b/Cantera/src/thermo/ThermoFactory.cpp
@@ -74,6 +74,8 @@
 
 #include "IdealSolnGasVPSS.h"
 
+#include <cstdlib>
+
 using namespace std;
 
 namespace Cantera {
diff --git a/Cantera/src/thermo/VPSSMgr_General.cpp b/Cantera/src/thermo/VPSSMgr_General.cpp
index 6db09888f..29dba2226 100644
--- a/Cantera/src/thermo/VPSSMgr_General.cpp
+++ b/Cantera/src/thermo/VPSSMgr_General.cpp
@@ -109,6 +109,32 @@ namespace Cantera {
     initLengths();
   }
 
+  /*!
+   *  Returns the vector of the
+   *  gibbs function of the reference state at the current temperature
+   *  of the solution and the reference pressure for the species.
+   *  units = J/kmol
+   *
+   * @param g   Output vector contain the Gibbs free energies
+   *            of the reference state of the species
+   *            length = m_kk, units = J/kmol.
+   */
+  void VPSSMgr_General::getGibbs_ref(doublereal *g) const {
+    doublereal _rt = GasConstant * m_tlast;
+    if (m_useTmpRefStateStorage) {
+      std::copy(m_g0_RT.begin(), m_g0_RT.end(), g);  
+      scale(g, g+m_kk, g, _rt);
+    } else {
+      for (int k = 0; k < m_kk; k++) {
+	PDSS *kPDSS = m_PDSS_ptrs[k];
+	kPDSS->setState_TP(m_tlast, m_plast);
+	double h0_RT = kPDSS->enthalpy_RT_ref();
+	double s0_R  = kPDSS->entropy_R_ref();
+	g[k] = _rt * (h0_RT - s0_R);
+      }
+    }
+  }
+
 
   void 
   VPSSMgr_General::initThermoXML(XML_Node& phaseNode, std::string id) {
diff --git a/Cantera/src/thermo/VPSSMgr_General.h b/Cantera/src/thermo/VPSSMgr_General.h
index 107c0a4ab..98bfb270c 100644
--- a/Cantera/src/thermo/VPSSMgr_General.h
+++ b/Cantera/src/thermo/VPSSMgr_General.h
@@ -147,6 +147,17 @@ namespace Cantera {
      */
     //@{
 
+    /*!
+     *  Returns the vector of the
+     *  gibbs function of the reference state at the current temperature
+     *  of the solution and the reference pressure for the species.
+     *  units = J/kmol
+     *
+     * @param g   Output vector contain the Gibbs free energies
+     *            of the reference state of the species
+     *            length = m_kk, units = J/kmol.
+     */
+    virtual void getGibbs_ref(doublereal *g) const ;
 
     //! @name Initialization Methods - For Internal use (VPStandardState)
     /*!