diff --git a/11-osm-im.md b/11-osm-im.md
index 855c7c7d99577875c7b219a6de6bdc071390e95f..06665b67bff08c61bbe5390111e9765513f4f66e 100644
--- a/11-osm-im.md
+++ b/11-osm-im.md
@@ -1,4 +1,4 @@
-# ANNEX 3: OSM Information Model
+# ANNEX 3: Reference of OSM Information Model
 
 ## YANG model in OSM repos
 
diff --git a/12-osm-nbi.md b/12-osm-nbi.md
index 42fb216bcbc3dee8a202ec8d63b652eebfaf865e..0f1b0bcb8897d6f0e59f2566595e8273ccc9a5cd 100644
--- a/12-osm-nbi.md
+++ b/12-osm-nbi.md
@@ -1,4 +1,4 @@
-# ANNEX 4: NBI API Description
+# ANNEX 4: Reference of NBI API Description
 
 ![link=https%3A%2F%2Fosm.etsi.org%2Fgitweb%2F%3Fp%3Dosm%2FSOL005.git%3Ba%3Dblob_plain%3Bf%3Dosm-openapi.yaml%3Bhb%3DHEAD](assets/750px-NBI.png)