documentclass{article}
usepackage[utf8]{inputenc}
usepackage[english]{babel}

usepackage{comment}

usepackage[
backend=biber,
style=alphabetic,
sorting=ynt
]{biblatex}
addbibresource{sample.bib}

title{Bibliography management: texttt{biblatex} package}
author{ShareLaTeX}
date{ }

begin{document}

maketitle

Using texttt{biblatex} you can display bibliography divided into sections,
depending of citation type.
Let's cite! Einstein's journal paper cite{einstein} and the Dirac's
book cite{dirac} are physics related items.
Next, textit{The LaTeX Companion} book cite{latexcompanion}, the Donald
Knuth's website cite{knuthwebsite}, textit{The Comprehensive Tex Archive
Network} (CTAN) cite{ctan} are LaTeX related items; but the others Donald
Knuth's items cite{knuth-fa,knuth-acp} are dedicated to programming.

medskip

printbibliography

end{document}