%% 
%%  Der Mathematiksatz mit LaTeX, 1. Auflage 2009
%% 
%%  Example 4-18-6 on page 69.
%% 
%%  Copyright (C) 2009 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.
%% 

\documentclass[]{ttctexa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{122.59192pt}
\AtBeginDocument{\setlength\parindent{0pt}}
\StartShownPreambleCommands

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