diff --git a/07-clifford1one/clase-09/README.md b/07-clifford1one/clase-09/README.md
index e603f05c..37d8b6eb 100644
--- a/07-clifford1one/clase-09/README.md
+++ b/07-clifford1one/clase-09/README.md
@@ -29,6 +29,11 @@ Bibliografía
 
 13. https://musiki.org.ar/Golan_Levin
 
+14. https://www.erpag.com/bill-of-materials-software
+
+15. https://www.youtube.com/watch?v=h0TRpGP8yH4
+
+    
 #Presentación
 
 https://www.figma.com/board/d2VNm2trjLyDlpML9uOzW5/Democracia?node-id=0-1&node-type=canvas&t=551rW3cJa8vbfGDm-0