This is the source .tex without the actual contents and with irrelevant section etc tags taken out

\documentclass{article}
	\title{}
	\author{}
	\date{}
	\usepackage{graphicx}
	\usepackage[colorlinks]{hyperref}
	\usepackage{hyperref}
	\hypersetup{citecolor=black}
	\hypersetup{urlcolor=blue}
	\hypersetup{linkcolor=black}
	\usepackage{multicol}
\begin{document}
\begin{abstract}
\cite{NSF_1}
\end{abstract}
\section{Figures and references}
\bibliographystyle{unsrt}
\bibliography{references}
\end{document}