diff --git a/Cite_body.php b/Cite_body.php
index 98331d122..9daf9217f 100644
--- a/Cite_body.php
+++ b/Cite_body.php
@@ -651,7 +651,7 @@ class Cite {
 	 * @return string XHTML ready for output
 	 */
 	function referencesFormat( $group ) {
-		if ( !$this->mRefs || !$this->mRefs[$group] ) {
+		if ( !$this->mRefs || !isset( $this->mRefs[$group] ) ) {
 			return '';
 		}