\documentclass{book}

 \usepackage{notoccite}
 \bibliographystyle{unsrt}
 \usepackage{multido}

\begin{document}
 \tableofcontents

 Cf.~\cite{DOC}. 

\chapter{Voir \cite{DOC2}}
 \multido{}{600}{blabla }

\bibliography{notoccitebib}
\end{document}