[AccessD] Bill of Material

I'm looking for a pattern (template?) for a bill of material. I have many
items, which in turn contain many items, etc. It needs to be "explodable"
showing all items, levels and quantities. I have found a couple of things
on-line, but they haven't really helped me; maybe I'm just too dense. If
you're aware of a pattern/template or a REALLY GOOD explanation of how to
create such a critter, please let me know. I'm getting desperate. Does
anyone know of a book with a full chapter on this kind of thing? I'd
actually prefer the detailed explanation (i.e., the knowledge) to the
template, but I would appreciate a usable template, so that I could go on
with my present project. 

Thanks.

Tom Ewald
Detroit Area