diff --git a/example/roget_components.cpp b/example/roget_components.cpp
index 8a34f22e..7a11353f 100644
--- a/example/roget_components.cpp
+++ b/example/roget_components.cpp
@@ -7,7 +7,8 @@
 // http://www.boost.org/LICENSE_1_0.txt)
 //=======================================================================
 
-#include <stdio.h>
+#include <cstdio>
+#include <cstring>
 #include <iostream>
 #include <boost/graph/stanford_graph.hpp>
 #include <boost/graph/strong_components.hpp>
diff --git a/example/topo-sort-with-sgb.cpp b/example/topo-sort-with-sgb.cpp
index 9b0ea8e5..b7d9ae66 100644
--- a/example/topo-sort-with-sgb.cpp
+++ b/example/topo-sort-with-sgb.cpp
@@ -8,8 +8,8 @@
 #include <vector>
 #include <string>
 #include <iostream>
-#include <boost/graph/topological_sort.hpp>
 #include <boost/graph/stanford_graph.hpp>
+#include <boost/graph/topological_sort.hpp>
 
 int
 main()
diff --git a/include/boost/graph/stanford_graph.hpp b/include/boost/graph/stanford_graph.hpp
index b2d3987d..01431737 100644
--- a/include/boost/graph/stanford_graph.hpp
+++ b/include/boost/graph/stanford_graph.hpp
@@ -46,6 +46,8 @@ extern "C" {
 #include <gb_books.h> /* graphs based on literature */
 #include <gb_econ.h> /* graphs based on economic data */
 #include <gb_games.h> /* graphs based on football scores */
+#undef ap /* avoid name clash with BGL parameter */
+        // ap ==> Vertex::u.I
 #include <gb_gates.h> /* graphs based on logic circuits */
 #undef val /* avoid name clash with g++ headerfile stl_tempbuf.h */
         // val ==> Vertex::x.I
@@ -92,6 +94,9 @@ namespace boost {
     typedef directed_tag directed_category;
     typedef sgb_traversal_tag traversal_category;
     typedef allow_parallel_edge_tag edge_parallel_category;
+    /** Return a null descriptor */
+    static vertex_descriptor null_vertex()
+    { return NULL; }
   };
   template <> struct graph_traits<sgb_const_graph_ptr> {
     typedef Vertex* vertex_descriptor;
@@ -107,6 +112,9 @@ namespace boost {
     typedef directed_tag directed_category;
     typedef sgb_traversal_tag traversal_category;
     typedef allow_parallel_edge_tag edge_parallel_category;
+    /** Return a null descriptor */
+    static vertex_descriptor null_vertex()
+    { return NULL; }
   };
 }