--- a/handouts/ho08.tex	Fri May 06 13:15:08 2016 +0100
+++ b/handouts/ho08.tex	Wed Jun 01 13:04:21 2016 +0100
@@ -5,6 +5,7 @@
 \usepackage{../data}
 
 %https://crypto.stanford.edu/cs251/
+%https://programmingblockchain.gitbooks.io/programmingblockchain/content/
 
 \begin{document}
 \fnote{\copyright{} Christian Urban, 2014, 2015}