%%
%% The LaTeX Companion, 2ed (second printing August 2004)
%%
%% Example 2-2-2 on page 26.
%%
%% Copyright (C) 2004 Frank Mittelbach, Michel Goossens,
%%    Johannes Braams, David Carlisle, and Chris Rowley
%%
%% 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{207.0pt}
\StartShownPreambleCommands
\renewcommand\thesubsection
    {\fbox{\thesection.\arabic{subsection}}}
\StopShownPreambleCommands
\begin{document}
\setcounter{section}{3}
\subsection{A mistake}\label{wrong}
Referencing a subsection in this format
produces a funny result as we can see
looking at subsection~\ref{wrong}.
We get a boxed reference.
\end{document}