\providecommand{\bysame}{\leavevmode\hbox to3em{\hrulefill}\thinspace}
\providecommand{\MR}{\relax\ifhmode\unskip\space\fi MR }
% \MRhref is called by the amsart/book/proc definition of \MR.
\providecommand{\MRhref}[2]{%
  \href{http://www.ams.org/mathscinet-getitem?mr=#1}{#2}
}
\providecommand{\href}[2]{#2}
\begin{thebibliography}{LLM21}

\bibitem[LLM21]{Lay}
David Lay, Stephen Lay, and Judi McDonald, \emph{Linear {A}lgebra and its
  {A}pplications}, Sixth edition, Pearson, 2021.

\end{thebibliography}
