tuned output;

--- a/src/Pure/Tools/bibtex.scala	Thu Dec 21 22:45:51 2017 +0100
+++ b/src/Pure/Tools/bibtex.scala	Thu Dec 21 22:56:51 2017 +0100
@@ -568,7 +568,7 @@
   {
     Isabelle_System.with_tmp_file("bib", "bib") { bib =>
       File.write(bib, snapshot.node.get_text)
-      html_output(List(bib), style = "unsortlist")
+      html_output(List(bib), style = "unsort")
     }
   }
 }