%%
%% The LaTeX Companion, 3ed
%%
%% Example 15-1-1 on page II-377 in "The standard \LaTeX {} bibliography environment".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{183.0pt}
% small headings for the example
\makeatletter
\renewcommand\section{\@startsection{section}{1}{\z@}%
                                    {-1.25ex \@plus-1ex \@minus-.2ex}%
                                    {.8ex}%
                                    {\normalsize\bfseries}}
\makeatother
%StartShownPreambleCommands

%StopShownPreambleCommands

\begin{document}
\cite{LGC97}, \cite{GUD97}
\begin{thebibliography}{2}
\bibitem{LGC97}  Goossens, M., S.~Rahtz,
    and F.~Mittelbach (1997).
  \newblock \emph{The \LaTeX{} Graphics Companion:
  Illustrating Documents with \TeX{} and
  PostScript}. \newblock Reading, MA, USA:
  Ad\-di\-son-Wes\-ley Longman.
\bibitem[GOO97]{GUD97} Goossens, M., B.~User,
  J.~Doe (1997). \newblock Ambiguous citations.
\end{thebibliography}
\end{document}