diff --git a/doc/src/sgml/biblio.sgml b/doc/src/sgml/biblio.sgml
index d85e3f0a24a..204970c2778 100644
--- a/doc/src/sgml/biblio.sgml
+++ b/doc/src/sgml/biblio.sgml
@@ -145,8 +145,8 @@
    </biblioentry>
 
    <biblioentry id="ULL88">
-    <title>Principles of Database and Knowledge</title>
-    <subtitle>Base Systems</subtitle>
+    <title>Principles of Database and Knowledge-Base Systems</title>
+    <subtitle>Classical Database Systems</subtitle>
     <titleabbrev>Ullman, 1988</titleabbrev>
     <authorgroup>
      <author>