--- a/doc/refman.tex
+++ b/doc/refman.tex
@@ -1,4 +1,6 @@
+\RequirePackage{ifpdf}
 \documentclass[11pt,twoside,a4paper]{book}
+\usepackage [latin1]{inputenc}
 
 %----------------------------------------------------------------------
 % $Revision: 1.94 $
