%&LaTeX
\documentclass{article}

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

\begin{document}

\begin{thebibliography}{1}

\bibitem{Richter+Ambrosius1972} Richter, H., \& Ambrosius, H. (1972). \textit{Ein hochmolekulares Immunglobulin des Flu{\ss}barsches (Perca fluviatilis L.)} (Vol. 26).

\end{thebibliography}

\end{document}

