%% 
%%  An UIT Edition example
%% 
%%  Example 04-18-6 on page 66.
%% 
%%  Copyright (C) 2010 Herbert Voss
%% 
%%  It 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.
%% 
%%  See http://www.latex-project.org/lppl.txt for details.
%% 
%% 
%% ==== 
% Show page(s) 1
%% 
\documentclass[]{exaarticle}
\pagestyle{empty}
\setlength\textwidth{129.70511pt}
\AtBeginDocument{\setlength\parindent{0pt}}
\StartShownPreambleCommands

\StopShownPreambleCommands
\begin{document}
\[ \sum_{%
  \makebox[0pt]{${{\scriptscriptstyle 1\le i\le p\atop {%
      {1\le j\le q\atop 1\le k\le r}}}}%
    $}}a_{ij}\mathbf{b_{jk}}c_{ki}
\]
\end{document}