referral
n 1: a person whose case has been referred to a specialist or
professional group; "the patient is a referral from Dr.
Bones"
2: a recommendation to consult the (professional) person or
group to whom one has been referred; "the insurance company
says that you need a written referral from your physician
before seeing a specialist"
3: the act of referring (as forwarding an applicant for
employment or referring a matter to an appropriate agency)