documentclass{beamer}
mode<presentation>
{
  usetheme{Szeged}
}

usepackage[english]{babel}
usepackage[backend=bibtex]{biblatex}

bibliography{sources.bib}

begin{document}
    begin{frame}
        This is a random textcite{Author:1}.
    end{frame}

    begin{frame}
        printbibliography{}
    end{frame}
end{document}

@ARTICLE{Author:1,
author={Doe, John},
journal={Hello},
title={No idea},
year={2015}}