diff --git a/PhysicsAnalysis/HeavyIonPhys/HIEventUtils/Root/HIEventShapeSummaryTool.cxx b/PhysicsAnalysis/HeavyIonPhys/HIEventUtils/Root/HIEventShapeSummaryTool.cxx
index 62aa22515bb2079d31d7a55ea7de92f345d151bd..be064d56186e55f75329c136f1ff58dd36fede8f 100644
--- a/PhysicsAnalysis/HeavyIonPhys/HIEventUtils/Root/HIEventShapeSummaryTool.cxx
+++ b/PhysicsAnalysis/HeavyIonPhys/HIEventUtils/Root/HIEventShapeSummaryTool.cxx
@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
 #include "HIEventUtils/HIEventShapeSummaryTool.h"
@@ -36,7 +36,7 @@ HIEventShapeSummaryTool::HIEventShapeSummaryTool(const std::string& n) : asg::As
 StatusCode HIEventShapeSummaryTool::summarize(const xAOD::HIEventShapeContainer* in, xAOD::HIEventShapeContainer* out) const
 {
   out->reserve(m_summary_list.size());
-  for(const auto itr : m_summary_list)
+  for(const auto& itr : m_summary_list)
   {
     xAOD::HIEventShape* es=new xAOD::HIEventShape();
     out->push_back(es);
@@ -53,7 +53,7 @@ StatusCode HIEventShapeSummaryTool::initialize()
 {
   //not optimal, but minimal code re-use, gets called only at initialization
   ATH_MSG_INFO("Configuring for summary");
-  for(const auto s : m_samp_names)
+  for(const auto& s : m_samp_names)
   {
     auto mItr=m_summary_list.find(s);
     if(mItr!=m_summary_list.end()) continue;
@@ -81,7 +81,7 @@ StatusCode HIEventShapeSummaryTool::initialize()
     }
   }
 
-  for(const auto s : m_subcalo_names)
+  for(const auto& s : m_subcalo_names)
   {
     auto mItr=m_summary_list.find(s);
     if(mItr!=m_summary_list.end()) continue;
@@ -160,7 +160,7 @@ std::string HIEventShapeSummaryTool::dumpList() const
      << std::setw(15) << "eta max"
      << std::setw(15) << "layer"
      << std::endl;
-  for(const auto itr : m_summary_list)
+  for(const auto& itr : m_summary_list)
   {
     ss << std::setw(15) << itr.second.name
        << std::setw(15) << itr.second.eta_min
diff --git a/PhysicsAnalysis/HeavyIonPhys/HIEventUtils/Root/HIVertexSelectionTool.cxx b/PhysicsAnalysis/HeavyIonPhys/HIEventUtils/Root/HIVertexSelectionTool.cxx
index 8297d7ae16f523ae7af0fa2fdfaf169d45b66d22..92b76af96e91eb027f2c7513357510df92febfda 100644
--- a/PhysicsAnalysis/HeavyIonPhys/HIEventUtils/Root/HIVertexSelectionTool.cxx
+++ b/PhysicsAnalysis/HeavyIonPhys/HIEventUtils/Root/HIVertexSelectionTool.cxx
@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
 
@@ -96,7 +96,7 @@ asg::AcceptData HI::HIVertexSelectionTool::accept( const xAOD::Vertex& vtx ) con
     bool countPt = m_minRmsPt >= 0.;
     int nPassed = 0; // cumulative total number of tracks passed
     double sumPtSq = 0.; // cumulative total of pt^2 of tracks passed
-    for ( const auto track : vtx.trackParticleLinks() ) {
+    for ( const auto& track : vtx.trackParticleLinks() ) {
       if ( !track.isValid() ) continue;
       if ( !m_trkSelTool->accept( **track, &vtx ) ) continue;