Hi,
The fact is that there is no really good CAML reference information.
You may be interested by
Patrick Tisseghem's CAML Query Builder V2 that lets you write a CAML query using a Graphical interface. Once you have built the query using this tool, you can copy the generated xml within the Enesys RS Data Extension query <list> element.
You can find some reference information (though not the best part of the documentation) in the Windows SharePoint Services SDK provided by Microsoft.
Regards,