diff --git a/51.md b/51.md
index e3b987ae..1b2928e3 100644
--- a/51.md
+++ b/51.md
@@ -35,7 +35,7 @@ For example, _mute list_ can contain the public keys of spammers and bad actors
 | DM relays         | 10050 | Where to receive [NIP-17](17.md) direct messages                      | `"relay"` (see [NIP-17](17.md))                                                   |
 | Good wiki authors | 10101 | [NIP-54](54.md) user recommended wiki authors                         | `"p"` (pubkeys)                                                                   |
 | Good wiki relays  | 10102 | [NIP-54](54.md) relays deemed to only host useful articles            | `"relay"` (relay URLs)                                                            |
-| Cart/wishlist     | 10402 | [NIP-99](99.md) listings the user wants to purchase or have purchased | `"listing"` (listing event IDs)                                                   |
+| Cart/wishlist     | 10402 | [NIP-99](99.md) listings the user wants to purchase or have purchased | `"listing"` ([NIP-99](99.md) listing event IDs)                                                   |
 
 ## Sets