%% Copyright 2016 Daniel Ballester Marques
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%% This work may be distributed and/or modified under the
%% conditions of the LaTeX Project Public License, either version 1.3
%% of this license or (at your option) any later version.
%% The latest version of this license is in
%%   http://www.latex-project.org/lppl.txt
%% and version 1.3 or later is part of all distributions of LaTeX
%% version 2005/12/01 or later.
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%% This work has the LPPL maintenance status `maintained'.
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%% The Current Maintainer of this work is Daniel Ballester Marques.

\documentclass{article}

\usepackage{pdfpagediff}

\begin{document}

\layerPages{NBR6023-2002.pdf}{NBR6023-2002_reference.pdf}

\end{document}

