diff --git a/HEN_HOUSE/egs++/geometry/egs_mesh/egs_mesh.h b/HEN_HOUSE/egs++/geometry/egs_mesh/egs_mesh.h
index c1b5b7a3d..191568472 100644
--- a/HEN_HOUSE/egs++/geometry/egs_mesh/egs_mesh.h
+++ b/HEN_HOUSE/egs++/geometry/egs_mesh/egs_mesh.h
@@ -59,6 +59,7 @@
 #include <memory>
 #include <sstream>
 #include <vector>
+#include <array>
 
 #include "egs_base_geometry.h"
 #include "egs_vector.h"
@@ -306,10 +307,10 @@ class EGS_MESH_EXPORT EGS_Mesh : public EGS_BaseGeometry {
                  << " \t2: " << n.C.x << " " << n.C.y << " " << n.C.z << "\n"
                  << " \t3: " << n.D.x << " " << n.C.y << " " << n.C.z << "\n"
                  << " \tNeighbour elements:\n"
-                 << " \t\tOn face 0: " << neighbours_[i][0] << "\n"
-                 << " \t\tOn face 1: " << neighbours_[i][1] << "\n"
-                 << " \t\tOn face 2: " << neighbours_[i][2] << "\n"
-                 << " \t\tOn face 3: " << neighbours_[i][3] << "\n"
+                 << " \t\tOn face 0: " << neighbours_.at(i).at(0) << "\n"
+                 << " \t\tOn face 1: " << neighbours_.at(i).at(1) << "\n"
+                 << " \t\tOn face 2: " << neighbours_.at(i).at(2) << "\n"
+                 << " \t\tOn face 3: " << neighbours_.at(i).at(3) << "\n"
                  << std::boolalpha
                  << " \tBoundary element: " << is_boundary(i) << "\n"
                  << " \tMedia index: "<< medium_indices_[i] << "\n";
@@ -363,10 +364,10 @@ class EGS_MESH_EXPORT EGS_Mesh : public EGS_BaseGeometry {
     Nodes element_nodes(int element) const {
         const auto &node_indices = elt_node_indices_.at(element);
         return Nodes {
-            nodes_.at(node_indices[0]),
-            nodes_.at(node_indices[1]),
-            nodes_.at(node_indices[2]),
-            nodes_.at(node_indices[3])
+            nodes_.at(node_indices.at(0)),
+            nodes_.at(node_indices.at(1)),
+            nodes_.at(node_indices.at(2)),
+            nodes_.at(node_indices.at(3))
         };
     }