diff --git a/10.md b/10.md
index 67b01f27..94db4fae 100644
--- a/10.md
+++ b/10.md
@@ -43,7 +43,7 @@ They are citing from this event.  `root-id` and `reply-id` are as above.
 Where:
 
  * `<event-id>` is the id of the event being referenced.
- * `<relay-url>` is the URL of a recommended relay associated with the reference. Clients SHOULD add a valid `<relay-URL>` field, but may instead leave it as `""`.
+ * `<relay-url>` is the URL of a recommended relay associated with the reference. Clients SHOULD add a valid `<relay-url>` field, but may instead leave it as `""`.
  * `<marker>` is optional and if present is one of `"reply"`, `"root"`, or `"mention"`.
  * `<pubkey>` is optional, SHOULD be the pubkey of the author of the referenced event