Index: index.html
===================================================================
--- index.html	(revision 900)
+++ index.html	(revision 901)
@@ -8,4 +8,5 @@
 	<li> 1. <a href="1_intro.html">Introduction</a>
 	<li> 2. <a href="2_topo.html">Detour search</a> (the topological aspect)
 	<li> 3. <a href="3_geo.html">Convex hull path</a> (geometric aspect)
+	<li> 4. <a href="4_appendix.html">Appendix</a>
 </ul>