%&LaTeX
\documentclass{article}

\usepackage[latin1]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{textcomp}

\begin{document}

\begin{thebibliography}{1}

\bibitem{Ladiges+Vogt1979} Ladiges, W., \& Vogt, D. (1979). \textit{Die S{\"u}{\ss}wasserfische Europas}. Hamburg, Berlin: Paul Parey Verlag.

\end{thebibliography}

\end{document}

