diff --git a/AABB_tree/include/CGAL/AABB_tree.h b/AABB_tree/include/CGAL/AABB_tree.h
index 5036319891d..89c78aa8984 100644
--- a/AABB_tree/include/CGAL/AABB_tree.h
+++ b/AABB_tree/include/CGAL/AABB_tree.h
@@ -648,7 +648,12 @@ public:
 		}
 		
 		//! Returns the datum (geometric object) represented `p`. 
-		typename AABBTraits::Primitive::Datum_reference datum(Primitive& p)const
+#ifndef DOXYGEN_RUNNING
+		typename internal::Primitive_helper<AABBTraits>::Datum_type 
+#else
+		typename AABBTraits::Primitive::Datum_reference 
+#endif
+		datum(Primitive& p)const
 		{
 		  return internal::Primitive_helper<AABBTraits>::
 		      get_datum(p, this->traits());