Continue work on Chapter 4.

CrossRef.sty

@@ -3,7 +3,7 @@
 
 % Cross references
 %#region
-	%\newcommand{\sectionRef}[2]{\ref{#1:#2}: #2}
+	\newcommand{\refPart}[2][Part~]{#1\ref{pt:#2}}
 	\newcommand{\refChapter}[2][Chapter~]{#1\ref{ch:#2}}
 	\newcommand{\refAppendix}[2][Appendix~]{#1\ref{ch:#2}}
 	\newcommand{\refSection}[2][Section~]{#1\ref{sec:#2}}
@@ -21,6 +21,9 @@
 			#3{#2}\label{#4:#1}
 		\fi
 	}
+	\newcommand{\lblPart}[2][]{
+		\lblGeneral[#1]{#2}{\part}{pt}
+	}
 	\newcommand{\lblChapter}[2][]{
 		\lblGeneral[#1]{#2}{\chapter}{ch}
 	}