\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]