diff --git a/LD/RDF_viewer/readme.md b/LD/RDF_viewer/readme.md
index 4b02327f..e5b4a55c 100644
--- a/LD/RDF_viewer/readme.md
+++ b/LD/RDF_viewer/readme.md
@@ -16,3 +16,4 @@
 
 ## my
 - https://github.com/bpmbpm/rdf-grapher/blob/main/ver1
+- https://github.com/bpmbpm/rdf-grapher/blob/main/ver1/rdf_viewer.md