%&LaTeX
\documentclass{article}

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

\begin{document}

\begin{thebibliography}{1}

\bibitem{Siegmann2010} Siegmann, B. (2010). \textit{Alkohol am Arbeitsplatz}  (B. B{\"u}rer, Ed.). Bern: Schweizer Radio DRS, DRS 1.

\end{thebibliography}

\end{document}

