%%
%% The LaTeX Companion, 3ed
%%
%% Example 3-3-9 on page I-160 in "Citations for acronyms".
%%
%% 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}%
                                    {.5ex}%
                                    {\normalfont\normalsize\bfseries}}
\makeatother
\setlength\textheight{9\baselineskip}
\bibliographystyle{plain}
%StartShownPreambleCommands
\usepackage{acro}
\acsetup{cite/group,cite/group/pre=,
         cite/group/cmd=\footcite}
\DeclareAcronym{tb}{short = TB-tricks,
  long = Dirty Tricks in the \TeX{} Book,
  cite = [App.\,D]{Knuth-CT-a} }
\newcommand\footcite[2][]
         {\footnote{See \cite[#1]{#2}.}}
%StopShownPreambleCommands

\begin{document}
\Ac{tb} and later refer to \ac{tb}.
\bibliography{tlc}
\end{document}