%&LaTeX
\documentclass{article}

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

\begin{document}

\begin{thebibliography}{1}

\bibitem{Haefeli_etal2011} Haefeli, J., Lischer, S., \& Schwarz, J. (2011). Early detection items and responsible gambling features for online gambling. \textit{International Gambling Studies}, (01.08.2011), 1--16.

\end{thebibliography}

\end{document}

