I hope this helps:
\documentclass{book}
\begin{document}
\part{ONE} \label{part:1}
\chapter{One}\label{part:1:ch:1}
Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et.
\section{1-One}
Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et, please see Part \ref{part:1}, Chapter \ref{part:1:ch:1}
\newpage
\setcounter{page}{1} % Page Number to 1
\setcounter{chapter}{0} % Next Chapter Number to 1
\part{TWO} \label{part:2}
\chapter{One}\label{part:2:ch:1}
Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et, please see Part \ref{part:1}, Chapter \ref{part:1:ch:1}.
\section{1-One}
Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et, please see Part \ref{part:1}, Chapter \ref{part:1:ch:1} and Part \ref{part:2}, Chapter \ref{part:2:ch:1}.
\end{document}
which produces:
