%&LaTeX
\documentclass{article}

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

\begin{document}

\begin{thebibliography}{10}

\bibitem{Zettler2001} Zettler, M. L. (2001). \textit{Der Edelkrebs (Astacus astacus) in Mecklenburg-Vorpommern} (Vol. 44).

\end{thebibliography}

\end{document}

