Does anyone know if the refrigerant for a 2003 Audi A4 is 134a?

Believe it or not, I can't seem to find the answer online.

Also, do you know of any online source of refill instructions. I can only find one port (near passenger side windshield) and hope that is the low pressure side. I have a very very slow leak.

At this point, I am assuming it is a standard fill procedure, but with Audi, everything I thought I knew about cars has been wrong.

Thanks...