diff --git a/book/syntax_exercises/013.md b/book/syntax_exercises/013.md
index a946c31..a097424 100644
--- a/book/syntax_exercises/013.md
+++ b/book/syntax_exercises/013.md
@@ -62,7 +62,6 @@ Here’s how the citation will appear for the example in the shared bibliography
 - `{cite:ts}` → **Textual, full authors**  
   → Moore [2023]
 
-> You can experiment with different reference styles in your `_config.yml` file to change how these look.
 ```
 
 ## Displaying the bibliography
@@ -77,7 +76,7 @@ Here’s how the citation will appear for the example in the shared bibliography
 
 
 `````{admonition} Avoiding duplicate citation warnings
-:class: note
+:class: warning
 
 If you use `{bibliography}` in multiple files, you might see warnings about duplicate citations when building your book. To avoid this, restrict the bibliography to only show references cited in the current page by adding a `:filter:` option: