Copyright for 1992 added
diff --git a/Include/objimpl.h b/Include/objimpl.h
index 18de355..3d1dceb 100644
--- a/Include/objimpl.h
+++ b/Include/objimpl.h
@@ -1,5 +1,5 @@
 /***********************************************************
-Copyright 1991 by Stichting Mathematisch Centrum, Amsterdam, The
+Copyright 1991, 1992 by Stichting Mathematisch Centrum, Amsterdam, The
 Netherlands.
 
                         All Rights Reserved