%%
%% The LaTeX Companion, 3ed
%%
%% Example 16-2-7 on page II-478 in "Customizing citation references and the bibliography with biblatex".
%%
%% 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}

% Use biber program
\makeatletter
\renewcommand\section{\@startsection{section}{1}{\z@}%
                                    {-1.25ex \@plus-1ex \@minus-.2ex}%
                                    {.8ex}%
                                    {\normalsize\bfseries}}
\makeatother

%StartShownPreambleCommands
\usepackage[style=trad-abbrv]{biblatex}
\addbibresource{tlc.bib}
\DeclareFieldFormat{labelnumberwidth}{#1\adddot}
%StopShownPreambleCommands

\begin{document}
\nocite{Knuth-CT-a}
\printbibliography
\end{document}