diff --git a/docs/fileformat_netcdf/metadata.rst b/docs/fileformat_netcdf/metadata.rst
index 6be92a117d5abfc58c6bef4d6fc7b54aaa38d6eb..c5e5b7e553cc60626a2cb48b351fb788c36ea9e9 100644
--- a/docs/fileformat_netcdf/metadata.rst
+++ b/docs/fileformat_netcdf/metadata.rst
@@ -28,7 +28,8 @@ CF Metadata Conventions
 -----------------------
 
 The `CF Metadata Conventions <https://cfconventions.org>`_ 
-longer list of metadata as global or variable attributes.
+requires a longer list of metadata as global or variable attributes as well as
+some additional concepts, like :ref:`boundary variables<time_bnds>`.
 
 
 ACDD convention