diff --git a/include/osg/GL2Extensions b/include/osg/GL2Extensions
index 7ed40918f..1e23e775e 100644
--- a/include/osg/GL2Extensions
+++ b/include/osg/GL2Extensions
@@ -18,6 +18,7 @@
 #ifndef OSG_GL2EXTENSIONS
 #define OSG_GL2EXTENSIONS 1
 
+#include <osg/Referenced>
 #include <osg/GL>
 
 namespace osg {
diff --git a/include/osg/Shader b/include/osg/Shader
index 77fc61dea..e79207dd7 100644
--- a/include/osg/Shader
+++ b/include/osg/Shader
@@ -20,6 +20,8 @@
 
 
 #include <osg/GL2Extensions>
+#include <osg/Object>
+#include <osg/buffered_value>
 
 #include <set>
 #include <string>