\documentclass{article}
\usepackage[english]{babel}
\usepackage[square,numbers]{natbib}
\bibliographystyle{abbrvnat}


\begin{document}


This document is an example of \texttt{natbib} package using in bibliography
management. Three items are cited: \textit{The \LaTeX\ Companion} book \cite{latexcompanion}, the Einstein journal paper \citet{einstein}, and the
Donald Knuth's website \cite{knuthwebsite}. The \LaTeX\ related items are
\cite{latexcompanion,knuthwebsite}.

\medskip

\bibliography{bib_10}

\end{document}


% bib_10.bib
@article{einstein,
author = "Albert Einstein",
title = "{Zur Elektrodynamik bewegter K{\"o}rper}. ({German})
[{On} the electrodynamics of moving bodies]",
journal = "Annalen der Physik",
volume = "322",
number = "10",
pages = "891--921",
year = "1905",
DOI = "http://dx.doi.org/10.1002/andp.19053221004"
}

@book{latexcompanion,
author = "Michel Goossens and Frank Mittelbach and Alexander Samarin",
title = "The \LaTeX\ Companion",
year = "1993",
publisher = "Addison-Wesley",
address = "Reading, Massachusetts"
}

@misc{knuthwebsite,
author = "Donald Knuth",
title = "Knuth: Computers and Typesetting",
url = "http://www-cs-faculty.stanford.edu/\~{}uno/abcde.html"
}