diff --git a/MuonSpectrometer/MuonGeoModel/MuonGeoModel/MuonDetectorFactory001.h b/MuonSpectrometer/MuonGeoModel/MuonGeoModel/MuonDetectorFactory001.h
index 2fe44352af1cc42d81c450fbd671d524b1c86963..fab4c5cf1ce318534b9b135de2a15516ae2d6962 100755
--- a/MuonSpectrometer/MuonGeoModel/MuonGeoModel/MuonDetectorFactory001.h
+++ b/MuonSpectrometer/MuonGeoModel/MuonGeoModel/MuonDetectorFactory001.h
@@ -65,8 +65,8 @@ public:
   inline void hasCSC(bool value);
   inline void hasSTgc(bool value);
   inline void hasMM(bool value);
-  inline void setABLinesAsciiSideA(std::string );
-  inline void setABLinesAsciiSideC(std::string );
+  inline void setABLinesAsciiSideA(const std::string& );
+  inline void setABLinesAsciiSideC(const std::string& );
 
 private: