diff --git a/iap21.md b/iap21.md
index 229ae1d6d..46fe69aa6 100644
--- a/iap21.md
+++ b/iap21.md
@@ -73,6 +73,8 @@
 - other interesting references
   - [[protocols.io]]
   - [[shader toy]]
+  - [[shader park]]
+  - [[repl.it]]
 
 
 ## [[2021-01-27]]