%&LaTeX
\documentclass{article}

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

\begin{document}

\begin{thebibliography}{1}

\bibitem{Helo_etal2013} Helo, J. C., Kovalenko, S. G., Hirsch, M., \& Pas, H. (2013). Neutrinoless double beta decay and lepton number violation at the LHC. \textit{Phys. Rev. D}, \textit{88}(1), 011901--5pp.

\end{thebibliography}

\end{document}

