%&LaTeX
\documentclass{article}

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

\begin{document}

\begin{thebibliography}{1}

\bibitem{Rojas_etal1990} {\textquotedblleft}\textit{The elemental composition of airborne particulate matter in the Atacama desert, Chile}{\textquotedblright}. Rojas CM, Figueroa L, Janssens KH, Van Espen PE, Adams FC, Van Grieken RE, The science of the total environment \textbf{91}, 251 (1990).   http://doi.org/10.1016/0048-9697(90)90302-B

\end{thebibliography}

\end{document}

