\chapter{Another Chapter}\label{chap_second}
\section{First Section}
This section has a theorem with its proof.
It is closely related to \Cref{thm:earth} from \Cref{chap_first}.
\begin{theorem}\label{thm:earth second}
The Earth is not flat.
\end{theorem}
\begin{IEEEproof}
Trivial.
\end{IEEEproof}
It also has a corollary.
\begin{corollary}
The Earth is round.
\end{corollary}
\begin{IEEEproof}
Follows from \Cref{thm:earth second}.
\end{IEEEproof}
Note (again) the use of the cleveref package here.
\section{Second Section}
This section has a remark.
\begin{remark}
Roses are red. See \Cref{lem:roses} for an explanation.
\end{remark}
\lipsum[5-9]