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

usepackage[
backend=biber,
style=alphabetic,
citestyle=alphabetic
]{biblatex}

addbibresource{sample.bib} %Imports bibliography file

begin{document}
section{First section}

First statement cite{gascuel97}, and a second statement cite{sokal58}.

printbibliography
end{document}