diff --git a/csl/science.csl b/csl/science.csl
index c367343070..0c7bce48fc 100644
--- a/csl/science.csl
+++ b/csl/science.csl
@@ -77,6 +77,9 @@
   </macro>
   <citation>
     <option name="collapse" value="citation-number"/>
+    <sort>
+      <key variable="citation-number"/>
+    </sort>
     <layout prefix="(" suffix=")" delimiter=", " font-style="italic">
       <text variable="citation-number" />
     </layout>