diff --git a/british-journal-of-anaesthesia.csl b/british-journal-of-anaesthesia.csl
index 6ff8f10bb24..77f51feb033 100644
--- a/british-journal-of-anaesthesia.csl
+++ b/british-journal-of-anaesthesia.csl
@@ -215,7 +215,7 @@
     <sort>
       <key variable="citation-number"/>
     </sort>
-    <layout delimiter=" " vertical-align="sup">
+    <layout delimiter=", " vertical-align="sup">
       <text variable="citation-number"/>
     </layout>
   </citation>