Before you go to one of the amps, you should read this:
http://massageplanet.net/showthread.php?t=79961
and this:
http://massageplanet.net/showthread.php?t=243134
Try reading more of the reviews to find a little out about the women and which ones you think you"d like. Post again if you have more questions.
I also see you don't have Premium Access, which will let you read the Rest of the Story, which is a far more detailed account of what took place during the session reviewed. To get premium access you should read this:
http://massageplanet.net/showthread.php?t=24103
None of the women working in the amps provide references that I know of; most indie providers would probably not accept one anyway. If you do a review of your amp session, it may improve your street cred with some of the indie providers.