diff --git a/34.md b/34.md
index 651407d..2a7f489 100644
--- a/34.md
+++ b/34.md
@@ -35,6 +35,10 @@ Except `d`, all tags are optional.
 
 Patches can be sent by anyone to any repository. Patches to a specific repository SHOULD be sent to the relays specified in that repository's announcement event's `"relays"` tag. Patch events SHOULD include an `a` tag pointing to that repository's announcement address.
 
+Patches in a patch set SHOULD include a NIP-10 `e` `reply` tag pointing to the previous patch. 
+
+The first patch revision in a patch revision SHOULD include a NIP-10 `e` `reply` to the original root patch.
+
 ```jsonc
 {
   "kind": 1617,