README.adoc in metanorma-nist-1.0.4 vs README.adoc in metanorma-nist-1.0.5

@@ -339,9 +339,15 @@
 `:supersedes:`::
 One or more NIST document that this NIST document standard supersedes; the superseded
 document may still remain in effect. Comma delimited.
 Format is document identifier, e.g. _SP 800-53A Rev. 1_
 
+NOTE: The distinction between `obsoletes` and `supersedes` is the withdrawal date of the
+original document (`obsoleted-date`); that means that the distinction is predictable given that external information.
+The distinction between `obsoleted-by` and `superseded-by`, in the same way, is made by
+the withdrawal date of the current document. Relaton does not differentiate between the two relations
+for that reason.
+
 `:superseded-by`::
 One or more corresponding NIST document that this NIST document standard is superseded by;
 this document may still remain in effect. Comma delimited.
 Format is document identifier, e.g. _SP 800-53A Rev. 1_
 Is *not* the relation between a withdrawn draft, and the next draft in the approval process