diff --git a/18.md b/18.md
index 4bf39ef7..41c94424 100644
--- a/18.md
+++ b/18.md
@@ -30,7 +30,7 @@ of the `mark` argument.
 
 `["q", <event-id>, <relay-url>, <pubkey>]`
 
-Quote reposts MUST include the [NIP-19](19.md) `nevent`, `note`, or `naddr` of the
+Quote reposts MUST include the [NIP-21](21.md) `nevent`, `note`, or `naddr` of the
 event in the content.
 
 ## Generic Reposts