diff --git a/content/da-07-dois.md b/content/da-07-dois.md
index de68bc9..501b48a 100644
--- a/content/da-07-dois.md
+++ b/content/da-07-dois.md
@@ -1,5 +1,7 @@
 <!-- .slide: id="dois" -->
+## * ~ * ~ * ~ * ~ * ~ * ~ * ~
 ## Digital Object Identifiers
+## * ~ * ~ * ~ * ~ * ~ * ~ * ~
 
 #--