diff --git a/content/notes/weekly-monthly-playbooks/index.md b/content/notes/weekly-monthly-playbooks/index.md
index 0d800ee..65429a5 100644
--- a/content/notes/weekly-monthly-playbooks/index.md
+++ b/content/notes/weekly-monthly-playbooks/index.md
@@ -22,3 +22,5 @@ references:
 ---
 
 {{<thumbnail notes "400x" />}}
+
+_Building a Second Brain_ (p. 215)