diff --git a/aconversions/src/fa2re/AbstractFAtoREConverter.h b/aconversions/src/fa2re/AbstractFAtoREConverter.h
index 0dee38f1d39f5e318bcbe93e83c9dead556bb3ee..e541a9c4b616cf354a9859aef90a71ccb614ca8e 100644
--- a/aconversions/src/fa2re/AbstractFAtoREConverter.h
+++ b/aconversions/src/fa2re/AbstractFAtoREConverter.h
@@ -20,7 +20,7 @@ public:
 protected:
     AbstractFAtoREConverter( const automaton::FSM & automaton );
 
-    const automaton::FSM & m_automaton;
+    const automaton::FSM m_automaton;
     regexp::RegExp m_re;
 };
 
diff --git a/aconversions/src/fa2rg/AbstractFAtoRGConverter.h b/aconversions/src/fa2rg/AbstractFAtoRGConverter.h
index 796e1fa84cfcc50a260fba08ceb52d6bc23d9fbd..0c0dd826da38209a04b968bafa518f6409562bad 100644
--- a/aconversions/src/fa2rg/AbstractFAtoRGConverter.h
+++ b/aconversions/src/fa2rg/AbstractFAtoRGConverter.h
@@ -25,7 +25,7 @@ public:
     ~AbstractFAtoRGConverter( void );
 
 protected:
-    const automaton::FSM & m_fsm;
+    const automaton::FSM m_fsm;
 };
 
 } /* namespace conversions */
diff --git a/aconversions/src/re2fa/AbstractREtoFAConverter.h b/aconversions/src/re2fa/AbstractREtoFAConverter.h
index e7fd3b85242f2ed5d8bd7bc72da692975fb46742..7d348a0981b03d2693e6f75c2d14c78f7d26cdca 100644
--- a/aconversions/src/re2fa/AbstractREtoFAConverter.h
+++ b/aconversions/src/re2fa/AbstractREtoFAConverter.h
@@ -21,7 +21,7 @@ public:
 protected:
     AbstractREtoFAConverter(const regexp::RegExp & re );
 
-    const regexp::RegExp & m_re;
+    const regexp::RegExp m_re;
     automaton::FSM m_fsm;
 };
 
diff --git a/aconversions/src/re2rg/AbstractREtoRGConverter.h b/aconversions/src/re2rg/AbstractREtoRGConverter.h
index e3a54c2a533d041cc9fdbe6bdd1beaf1f2aaac05..a97b41cce5df8031d37abab633981f9f933d1207 100644
--- a/aconversions/src/re2rg/AbstractREtoRGConverter.h
+++ b/aconversions/src/re2rg/AbstractREtoRGConverter.h
@@ -24,7 +24,7 @@ public:
 protected:
     AbstractREtoRGConverter( const regexp::RegExp & re );
 
-    const regexp::RegExp & m_re;
+    const regexp::RegExp m_re;
 };
 
 } /* namespace conversions */
diff --git a/aconversions/src/rg2fa/lrg2fa/AbstractLRGtoFAConverter.h b/aconversions/src/rg2fa/lrg2fa/AbstractLRGtoFAConverter.h
index 4960994ad892fdae2f26eec73a6008fcf493f887..e88a28f5e1593aeb3ad003f0524dcc7d33b7b0bf 100644
--- a/aconversions/src/rg2fa/lrg2fa/AbstractLRGtoFAConverter.h
+++ b/aconversions/src/rg2fa/lrg2fa/AbstractLRGtoFAConverter.h
@@ -22,7 +22,7 @@ public:
 
 protected:
     AbstractLRGtoFAConverter( const grammar::LeftRegularGrammar & lrg );
-    const grammar::LeftRegularGrammar & m_grammar;
+    const grammar::LeftRegularGrammar m_grammar;
 
 };
 
diff --git a/aconversions/src/rg2fa/rrg2fa/AbstractRRGtoFAConverter.h b/aconversions/src/rg2fa/rrg2fa/AbstractRRGtoFAConverter.h
index c1bf9528dadee746001ba7997c63128e50ce8087..54347239fa655d8f02c10d88531dd9cded66e554 100644
--- a/aconversions/src/rg2fa/rrg2fa/AbstractRRGtoFAConverter.h
+++ b/aconversions/src/rg2fa/rrg2fa/AbstractRRGtoFAConverter.h
@@ -22,7 +22,7 @@ public:
 
 protected:
     AbstractRRGtoFAConverter( const grammar::RightRegularGrammar & rrg );
-    const grammar::RightRegularGrammar & m_grammar;
+    const grammar::RightRegularGrammar m_grammar;
 };
 
 } /* namespace conversions */
diff --git a/aconversions/src/rg2re/lrg2re/AbstractLRGtoREConverter.h b/aconversions/src/rg2re/lrg2re/AbstractLRGtoREConverter.h
index 67c2620ae2bb0ee29c0e6b72f323a7d39a5ba2b9..f6d406336b86eb6e5374e4b1da896b08dddb8add 100644
--- a/aconversions/src/rg2re/lrg2re/AbstractLRGtoREConverter.h
+++ b/aconversions/src/rg2re/lrg2re/AbstractLRGtoREConverter.h
@@ -22,7 +22,7 @@ public:
 
 protected:
     AbstractLRGtoREConverter( const grammar::LeftRegularGrammar & lrg );
-    const grammar::LeftRegularGrammar & m_grammar;
+    const grammar::LeftRegularGrammar m_grammar;
 };
 
 } /* namespace conversions */
diff --git a/aconversions/src/rg2re/rrg2re/AbstractRRGtoREConverter.h b/aconversions/src/rg2re/rrg2re/AbstractRRGtoREConverter.h
index 2dea0db5181c9ce5f97d6f27e6677d3ae52e8cb8..83de063ecdaaea294493887c225807247a06148d 100644
--- a/aconversions/src/rg2re/rrg2re/AbstractRRGtoREConverter.h
+++ b/aconversions/src/rg2re/rrg2re/AbstractRRGtoREConverter.h
@@ -23,7 +23,7 @@ public:
 protected:
     AbstractRRGtoREConverter( const grammar::RightRegularGrammar & rrg );
 
-    const grammar::RightRegularGrammar & m_grammar;
+    const grammar::RightRegularGrammar m_grammar;
 };
 
 } /* namespace conversions */
diff --git a/aconversions/src/rg2rg/lrg2rrg/AbstractLRGtoRRGConverter.h b/aconversions/src/rg2rg/lrg2rrg/AbstractLRGtoRRGConverter.h
index f13f242aaf37e8fdb3669b0e9d7577bb2e3d41e4..637f25bedc1a3f8016becb872f015442be642782 100644
--- a/aconversions/src/rg2rg/lrg2rrg/AbstractLRGtoRRGConverter.h
+++ b/aconversions/src/rg2rg/lrg2rrg/AbstractLRGtoRRGConverter.h
@@ -25,7 +25,7 @@ public:
 protected:
     AbstractLRGtoRRGConverter( const grammar::LeftRegularGrammar & lrg );
 
-    const grammar::LeftRegularGrammar & m_lrg;
+    const grammar::LeftRegularGrammar m_lrg;
     grammar::RightRegularGrammar m_rrg;
 };
 
diff --git a/aconversions/src/rg2rg/rrg2lrg/AbstractRRGtoLRGConverter.h b/aconversions/src/rg2rg/rrg2lrg/AbstractRRGtoLRGConverter.h
index 37d0468c03f4cc89946692f9db96b309777189cb..0c2cca11c2cf1c7ef3f5fcdfdcd3c182a98903a0 100644
--- a/aconversions/src/rg2rg/rrg2lrg/AbstractRRGtoLRGConverter.h
+++ b/aconversions/src/rg2rg/rrg2lrg/AbstractRRGtoLRGConverter.h
@@ -24,7 +24,7 @@ public:
     virtual grammar::LeftRegularGrammar convert( void ) = 0;
 
 protected:
-    const grammar::RightRegularGrammar & m_rrg;
+    const grammar::RightRegularGrammar m_rrg;
     grammar::LeftRegularGrammar m_lrg;
 };