\part{The First Part}
\label{part:first}

The following are the contents for the first part.

\chapter{The First Chapter}
\label{chapter:first}

Say hello to the first chapter. Test command: $\test$.

\begin{theorem}[Example Theorem]
    \label{theorem:example}

    Example theorem content.
\end{theorem}
\begin{proof}
    See \cite[Page 120]{Example}.
\end{proof}