The normal behavior of BibTeX is set in such a way that unreferenced entries in the .bib file will not be displayed in the bibliography section. But what if we need to print even the unreferenced entries in the .bib file also made part of the bibliographic section? For that we have a command called \nocite{*}. This command will override the default behavior of BibTeX such that even an referenced entries in the .bib file will be added in the bibliographic section in the DVI or PDF file produced. The script below shows the working of \nocite{*} command. The TeX file uses a .bib file called bib1.bib.
\documentclass{article}
\usepackage{natbib}
\title{Sample Article}
\author{D}
\begin{document}
\maketitle
\nocite{*}
Here the entries in the Bibfile are not referenced.
But they are shown in the reference section because we
use \textbackslash cite\{*\} command.
\bibliographystyle{plain}
\bibliography{bib1.bib}
\end{document}
