diff --git a/include/boost/geometry/strategies/covered_by.hpp b/include/boost/geometry/strategies/covered_by.hpp
index a878b26c8..a5aae7703 100644
--- a/include/boost/geometry/strategies/covered_by.hpp
+++ b/include/boost/geometry/strategies/covered_by.hpp
@@ -53,7 +53,7 @@ struct default_strategy
 {
     BOOST_MPL_ASSERT_MSG
         (
-            false, NOT_IMPLEMENTED_FOR_THIS_TYPES
+            false, NOT_IMPLEMENTED_FOR_THESE_TYPES
             , (types<GeometryContained, GeometryContaining>)
         );
 };
diff --git a/include/boost/geometry/strategies/within.hpp b/include/boost/geometry/strategies/within.hpp
index 0852a22d2..d625bc40e 100644
--- a/include/boost/geometry/strategies/within.hpp
+++ b/include/boost/geometry/strategies/within.hpp
@@ -52,7 +52,7 @@ struct default_strategy
 {
     BOOST_MPL_ASSERT_MSG
         (
-            false, NOT_IMPLEMENTED_FOR_THIS_TYPES
+            false, NOT_IMPLEMENTED_FOR_THESE_TYPES
             , (types<GeometryContained, GeometryContaining>)
         );
 };