diff --git a/rdf.md b/rdf.md
index 64fa41e69..88aa10332 100644
--- a/rdf.md
+++ b/rdf.md
@@ -52,6 +52,7 @@
   	- "Therefore, RDF uses subject instead of object (or entity) in contrast to the typical approach of an entity–attribute–value model in object-oriented design: entity (sky), attribute (color), and value (blue)."
 	- RDF is an [[abstract model]]. There are several [[rdf serialization formats]].
 	- See also: [[W3C]]'s [[Semantic Web]] activity: an evolutionary stage of the [[World Wide Web]] in which "automated software can store, exchange, and use [[machine-readable information]] distributed throughout the [[Web]], in turn enabling users to deal with the information with greater [[efficiency]] and [[certainty]]." Also used in [[knowledge management applications]] unrelated to Semantic Web activity.
+	- [[RDFS]] and [[OWL]] are ontology languages built opon RDF. 
 
 
 [//begin]: # "Autogenerated link references for markdown compatibility"
@@ -70,4 +71,5 @@
 [tools]: tools "Tools"
 [wikipedia]: wikipedia "Wikipedia"
 [rdf serialization formats]: rdf-serialization-formats "Rdf Serialization Formats"
+[knowledge management applications]: knowledge-management-applications "Knowledge Management Applications"
 [//end]: # "Autogenerated link references"
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