LaTeX Warning: Empty thebibliography' environment on input line 3

I have a problem with my bibliography. Though my bib file is not empty, I get the message that it is. Also my .bbl file is empty.

This is my document:

  \documentclass[10pt, a4paper]{Thesis}

\begin{document}

\cite{Author2010}

\bibliographystyle{unsrt}
\bibliography{testbib.bib}

\end{document}


And this is my bib file:

 @BOOK{Author2010,
author = {Author, This},
pages = {301},
publisher = {Springer},
title = {{Book}},
year = {2010}
}

• Welcome to TeX.SX! You're missing a comma at the end of the author line and BibTeX should have warned about the problem. – egreg Feb 28 '14 at 15:41
• Thank you. Sorry, this was a small error in my minimal example, but not the solution to my problem. – BramMooij Feb 28 '14 at 15:43

The correct syntax is \bibliography{testbib} (without the .bib` ending).