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Hi all,

I read all topics related with question mark references. However, I couldn't fix mine.

Here is my code which is saved as "si_hap.tex".

\usepackage{natbib}
\bibpunct{(}{)}{;}{a}{,}{,}
\newpage
\bibliographystyle{chicago}
\bibliography{si_hap}

Here is my bibliography database file which ...