diff --git a/src/external/TFitPofB-lib/include/TBofZCalc.h b/src/external/TFitPofB-lib/include/TBofZCalc.h
index bf30ce8f..b54e41a5 100644
--- a/src/external/TFitPofB-lib/include/TBofZCalc.h
+++ b/src/external/TFitPofB-lib/include/TBofZCalc.h
@@ -5,7 +5,7 @@
   Author: Bastian M. Wojek
   e-mail: bastian.wojek@psi.ch
 
-  2008/06/30
+  2008/11/07
 
 ***************************************************************************/
 
@@ -104,4 +104,16 @@ public:
 
 };
 
+//--------------------
+// Class "for Meissner screening" in a thin superconducting film - four layers with four different lambdas
+//--------------------
+
+class TLondon1D_4L : public TBofZCalc {
+
+public:
+
+  TLondon1D_4L(unsigned int, const vector<double>& );
+
+};
+
 #endif // _BofZCalc_H_
diff --git a/src/external/TFitPofB-lib/include/TLondon1D.h b/src/external/TFitPofB-lib/include/TLondon1D.h
index 8bf3cdd7..f151ee50 100644
--- a/src/external/TFitPofB-lib/include/TLondon1D.h
+++ b/src/external/TFitPofB-lib/include/TLondon1D.h
@@ -140,4 +140,54 @@ private:
   ClassDef(TLondon1D3LS,1)
 };
 
+class TLondon1D4L : public PUserFcnBase {
+
+public:
+  // default constructor
+  TLondon1D4L();
+  ~TLondon1D4L();
+
+  double operator()(double, const vector<double>&) const;
+
+private:
+  mutable vector<double> fPar;
+  TTrimSPData *fImpProfile;
+  TPofTCalc *fPofT;
+  mutable bool fCalcNeeded;
+  mutable bool fFirstCall;
+  mutable vector<double> fParForPofT;
+  mutable vector<double> fParForBofZ;
+  mutable vector<double> fParForPofB;
+  string fWisdom;
+  unsigned int fNSteps;
+  mutable bool fLastFourChanged;
+
+  ClassDef(TLondon1D4L,1)
+};
+
+class TLondon1D3LSub : public PUserFcnBase {
+
+public:
+  // default constructor
+  TLondon1D3LSub();
+  ~TLondon1D3LSub();
+
+  double operator()(double, const vector<double>&) const;
+
+private:
+  mutable vector<double> fPar;
+  TTrimSPData *fImpProfile;
+  TPofTCalc *fPofT;
+  mutable bool fCalcNeeded;
+  mutable bool fFirstCall;
+  mutable vector<double> fParForPofT;
+  mutable vector<double> fParForBofZ;
+  mutable vector<double> fParForPofB;
+  string fWisdom;
+  unsigned int fNSteps;
+  mutable bool fWeightsChanged;
+
+  ClassDef(TLondon1D3LSub,1)
+};
+
 #endif //_TLondon1D_H_
diff --git a/src/external/TFitPofB-lib/include/TLondon1DLinkDef.h b/src/external/TFitPofB-lib/include/TLondon1DLinkDef.h
index 3af86b93..2097638d 100644
--- a/src/external/TFitPofB-lib/include/TLondon1DLinkDef.h
+++ b/src/external/TFitPofB-lib/include/TLondon1DLinkDef.h
@@ -21,6 +21,8 @@
 #pragma link C++ class TLondon1D2L+;
 #pragma link C++ class TLondon1D3L+;
 #pragma link C++ class TLondon1D3LS+;
+#pragma link C++ class TLondon1D4L+;
+#pragma link C++ class TLondon1D3LSub+;
 
 #endif //__CINT__
 // root dictionary stuff --------------------------------------------------
diff --git a/src/external/TFitPofB-lib/include/TPofBCalc.h b/src/external/TFitPofB-lib/include/TPofBCalc.h
index 9d256605..5a273cef 100644
--- a/src/external/TFitPofB-lib/include/TPofBCalc.h
+++ b/src/external/TFitPofB-lib/include/TPofBCalc.h
@@ -16,6 +16,7 @@
 #include "TTrimSPDataHandler.h"
 
 #define gBar 0.0135538817
+#define pi 3.14159265358979323846
 
 class TPofBCalc {
 
@@ -32,6 +33,7 @@ public:
   double GetBmin() const {return fBmin;}
   double GetBmax() const {return fBmax;}
   void ConvolveGss(double);
+  void AddBackground(double, double, double);
 
 private:
   vector<double> fB;
diff --git a/src/external/TFitPofB-lib/include/TTrimSPDataHandler.h b/src/external/TFitPofB-lib/include/TTrimSPDataHandler.h
index c87e7f65..cd46b510 100644
--- a/src/external/TFitPofB-lib/include/TTrimSPDataHandler.h
+++ b/src/external/TFitPofB-lib/include/TTrimSPDataHandler.h
@@ -32,6 +32,7 @@ public:
   vector<double> DataNZ(double) const;
   vector<double> OrigDataNZ(double) const;
   void WeightLayers(double, const vector<double>&, const vector<double>&) const;
+  double LayerFraction(double, unsigned int, const vector<double>&) const;
   double GetNofZ(double, double) const;
   void Normalize(double) const;
   bool IsNormalized(double) const;