--- a/hws/hw09.tex	Mon Oct 19 23:49:25 2015 +0100
+++ b/hws/hw09.tex	Tue Oct 20 00:01:56 2015 +0100
@@ -6,6 +6,8 @@
 
 \section*{Homework 9}
 
+\HEADER
+
 \begin{enumerate}
 \item Describe what is meant by \emph{eliminating tail
       recursion}, when such an optimization can be applied and