Linking to an biblioentry resource, howto?

Dear list,

I have an external hard drive with a huge amount of digital documents.
At the moment, I am getting more and more lost and it becomes difficult
for me to organise all these files.

Now I would like to create an overview document with the help of docbook
and its biblioentry element. It allows me to describe all information I
need.

The only question I have is: how can I spezify the real location of the
document like ../product/standard.pdf? Is there a element which is
intended to be used for this? Or would it be better to add a new element
with this own namespace for this purpose?

Bye

Oliver