diff --git a/README.md b/README.md
index 38a03173..555f006d 100644
--- a/README.md
+++ b/README.md
@@ -163,7 +163,7 @@ Please update these lists when proposing NIPs introducing new event kinds.
 | `k`               | kind number (string)                 | --                   | [18](18.md), [72](72.md) |
 | `l`               | label, label namespace               | annotations          | [32](32.md)              |
 | `L`               | label namespace                      | --                   | [32](32.md)              |
-| `r`               | a reference (URL, etc)               | --                   |                          |
+| `r`               | a reference (URL, etc)               | petname              |                          |
 | `r`               | relay url                            | marker               | [65](65.md)              |
 | `t`               | hashtag                              | --                   |                          |
 | `amount`          | millisatoshis, stringified           | --                   | [57](57.md)              |