add a relevant "see also" link

Doc/mac/libmacui.tex

@@ -191,6 +191,15 @@ folder selected or \constant{None} if the user cancelled. See
 \function{AskFileForOpen()} for a description of the arguments.
 \end{funcdesc}
 
+
+\begin{seealso}
+  \seetitle
+  [http://developer.apple.com/documentation/Carbon/Reference/Navigation_Services_Ref/]
+  {Navigation Services Reference}{Programmer's reference documentation
+  for the Navigation Services, a part of the Carbon framework.}
+\end{seealso}
+
+
 \subsection{ProgressBar Objects \label{progressbar-objects}}
 
 \class{ProgressBar} objects provide support for modeless progress-bar