%&LaTeX
\documentclass{article}

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

\begin{document}

\begin{thebibliography}{1}

\bibitem{Nelson_etal1974} {\textquotedblleft}\textit{Elemental analysis of aerosols using proton-scattering}{\textquotedblright}. Nelson JW, Williams I, Johansson TB, Van Grieken RE, IEEE transactions on nuclear science \textbf{Ns21}, 618 (1974).   http://doi.org/10.1109/TNS.1974.4327522

\end{thebibliography}

\end{document}

