diff --git a/lisp/my/my-org-article.el b/lisp/my/my-org-article.el
index 064d4f66..b26b642a 100644
--- a/lisp/my/my-org-article.el
+++ b/lisp/my/my-org-article.el
@@ -47,7 +47,7 @@
   :type 'integer
   :safe #'integerp)
 
-(defcustom my-org-article-export-with-sub-superscripts {}
+(defcustom my-org-article-export-with-sub-superscripts '{}
   "See `org-export-with-sub-superscripts'."
   :group 'my-org-export-article
   :version "24.4"