%&LaTeX
\documentclass{article}

\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{textcomp}

\begin{document}

\begin{thebibliography}{1}

\bibitem{Piontek_etal2014} Piontek, F., M{\"u}ller, C., Pugh, T. A., Clark, D. B., Deryng, D., Elliott, J., et al. (2014). Multisectoral climate impact hotspots in a warming world. \textit{Proc. Natl. Acad. Sci. U. S. A.}, \textit{111}(9), 3233--3238.

\end{thebibliography}

\end{document}

