%%
%% The LaTeX Companion, 3ed
%%
%% Example A-3-4 on page II-662 in "LR boxes".
%%
%% 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{159.0pt}
%StartShownPreambleCommands

%StopShownPreambleCommands

\begin{document}
\centering
A sentence.\makebox[0pt][l]{\textsuperscript{123}}\\
Some more text in the middle.                     \\
\makebox[0cm][r]{\textsuperscript{321}}A sentence.
\end{document}