\vspace*{2ex}
-\centerline{\color{red}(work in progress, to be updated)}\\[3ex]
+\centerline{\color{red}(work in progress, to be updated)}
+
+\medskip
\centerline{\url{https://fleuret.org/public/culture/culture.pdf}}
\section*{Appendix}
-The code is available at\\[-2ex]
+The code is available at
+
+\medskip
\centerline{\url{https://fleuret.org/git/culture}}