For HCP targeted advertising, references are required in the final layout of the piece. Yes, as you said, this entails a reference list at the end of the piece and the corresponding superscripts throughout the piece. An alternative is to use the superscripts throughout the piece but include the corresponding reference list in a web location corresponding to a URL presented on the piece. See the PAAB code sections 4.4.3 to 4.4.7.
This is required for adherence to PAAB code section 3.3 (i.e. an HCP would need to know which reference to request from the manufacturer if he/she wanted additional info or wanted to test the evidentiary basis for a claim).