diff -r 5820841f21fd -r 8cf9d9a3a327 doc-src/TutorialI/preface.tex
--- a/doc-src/TutorialI/preface.tex	Thu Dec 20 15:17:48 2001 +0100
+++ b/doc-src/TutorialI/preface.tex	Thu Dec 20 15:20:07 2001 +0100
@@ -48,16 +48,16 @@
 derived almost entirely from output generated in this way.
 
 Isabelle's
-\href{http://isabelle.in.tum.de/}{web site}
+\hfootref{http://isabelle.in.tum.de/}{web site}
 contains links to the download area and to documentation and other
 information.  Most Isabelle sessions are now run from within David
 Aspinall's wonderful user interface,
-\href{http://www.proofgeneral.org/}{Proof General}.  This book says
+\hfootref{http://www.proofgeneral.org/}{Proof General}.  This book says
 very little about Proof General, which has its own documentation.  In
 order to run Isabelle, you will need a Standard ML compiler.  We
-recommend \href{http://www.polyml.org/}{Poly/ML}, which is free and
+recommend \hfootref{http://www.polyml.org/}{Poly/ML}, which is free and
 gives the best performance.  The other supported compiler is
-\href{http://cm.bell-labs.com/cm/cs/what/smlnj/index.html}{Standard
+\hfootref{http://cm.bell-labs.com/cm/cs/what/smlnj/index.html}{Standard
 ML of New Jersey}.
 
 This tutorial owes a lot to the constant discussions with and the valuable