diff --git a/Event/EventCommonAlgs/src/I4MomDumper.cxx b/Event/EventCommonAlgs/src/I4MomDumper.cxx
index 9c09222e109fc0d024c95cdf8c9639e5e7c8e100..9cff05b2071aa9516c4432bc4bf36c2a60609209 100644
--- a/Event/EventCommonAlgs/src/I4MomDumper.cxx
+++ b/Event/EventCommonAlgs/src/I4MomDumper.cxx
@@ -195,7 +195,7 @@ I4MomDumper::dump( const std::string& collName )
   }
 
   // sorting the collection by Pt
-  typedef std::set<I4Momentum*, P4Sorters::Descending::Pt> Coll_t;
+  typedef std::set<const I4Momentum*, P4Sorters::Descending::Pt> Coll_t;
   Coll_t i4moms( coll->begin(), coll->end() );
 
   if ( m_display == Display::EEtaPhiM ) {
diff --git a/Event/EventCommonAlgs/src/INav4MomDumper.cxx b/Event/EventCommonAlgs/src/INav4MomDumper.cxx
index d4c1d7d904b8334ea717856bced841daddc17448..32e38d823231a7e0f88972173eab86bd8fb303d0 100755
--- a/Event/EventCommonAlgs/src/INav4MomDumper.cxx
+++ b/Event/EventCommonAlgs/src/INav4MomDumper.cxx
@@ -178,7 +178,7 @@ INav4MomDumper::dump( const std::string& collName )
   }
 
   // sorting the collection by Pt
-  typedef std::set<INavigable4Momentum*, P4Sorters::Descending::Pt> Coll_t;
+  typedef std::set<const INavigable4Momentum*, P4Sorters::Descending::Pt> Coll_t;
   Coll_t inav4moms( coll->begin(), coll->end() );
 
   FourMomUtils::dump( out, inav4moms );