How do I find out what Referees I chose?

Can any lab be a referee? I have 3 that a relatively close (within a 2 hour drive) but I don’t think they are on the referee list… If I was able to do so, I would choose these labs and just go a visit each one for a couple of hours.

On a side note, I just got some information from my CPA who is helping me with the legal paperwork. I am now an official incorporation and heard back from the IRS (in the US) that they received my forms to become a 501C3.