pricing a jerry garcia guitar

[asofel]

I'm trying to finding out just how much a guitar that was possibly used but definitely signed by Jerry Garcia is worth.
Its an alvarez yairi dy 99, location is Florida, and I'm wondering if anyone has any suggestions how to go about finding out something like this. Thoughts?

[slickpoppa]

How do you know it is authentic? Are you interested in buying it?

[asofel]

this is a task for a friend actually. she says the owner has an invoice for it. i suppose he has certificates/etc.