diff --git a/md/annex-c.md b/md/annex-c.md
index 46b56cb6ab31d0b9a19528b9c5aff9856a6576f8..c5c77b05bbf30a3db62927dfef84cf5b6870bef0 100644
--- a/md/annex-c.md
+++ b/md/annex-c.md
@@ -29,7 +29,7 @@ Figure: Reference example
 As per the algorithms described above and as per the rules for generating the
 JSON-LD representation of NGSI-LD entities the above graph will result in the
 following JSON-LD representations. The syntax has been checked using the JSON-LD
-Playground tool [i.21].
+Playground tool [i.19].
 
 ### C.2.2 Vehicle Entity