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diff --git a/src/stlplus/persistence/persistent_xref.tpp b/src/stlplus/persistence/persistent_xref.tpp
new file mode 100644
index 0000000..e12639d
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+++ b/src/stlplus/persistence/persistent_xref.tpp
@@ -0,0 +1,51 @@
+////////////////////////////////////////////////////////////////////////////////
+
+//   Author:    Andy Rushton
+//   Copyright: (c) Southampton University 1999-2004
+//              (c) Andy Rushton           2004-2009
+//   License:   BSD License, see ../docs/license.html
+
+//   format: magic_key [ data ]
+
+////////////////////////////////////////////////////////////////////////////////
+#include "persistent_int.hpp"
+
+namespace stlplus
+{
+
+  ////////////////////////////////////////////////////////////////////////////////
+
+  template<typename T>
+  void dump_xref(dump_context& context, const T* const data)
+    throw(persistent_dump_failed)
+  {
+    // register the address and get the magic key for it
+    std::pair<bool,unsigned> mapping = context.pointer_map(data);
+    // if this is the first view of this pointer, simply throw an exception
+    if (!mapping.first) throw persistent_dump_failed("tried to dump a cross-reference not seen before");
+    // otherwise, just dump the magic key
+    dump_unsigned(context,mapping.second);
+  }
+
+  ////////////////////////////////////////////////////////////////////////////////>
+
+  template<typename T>
+  void restore_xref(restore_context& context, T*& data)
+    throw(persistent_restore_failed)
+  {
+    // Note: I do not try to delete the old data because this is a cross-reference
+    // get the magic key
+    unsigned magic = 0;
+    restore_unsigned(context,magic);
+    // now lookup the magic key to see if this pointer has already been restored
+    // null pointers are always flagged as already restored
+    std::pair<bool,void*> address = context.pointer_map(magic);
+    // if this is the first view of this pointer, simply throw an exception
+    if (!address.first) throw persistent_restore_failed("tried to restore a cross-reference not seen before");
+    // seen before, so simply assign the old address
+    data = (T*)address.second;
+  }
+
+  ////////////////////////////////////////////////////////////////////////////////
+
+} // end namespace stlplus