after 1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.Qc2 c5 5.dxc5 Na6 6.a3 Qa5 7.Bd2 Nxc5 David Vigorito gives 8.0-0-0!? and shows the game Shirov - Bauer after 8...Bxc3 9.Bxc3 Qa4 he says: "Shirov suggests 9...Qc7 or 9...Qb6 but these moves have not attracted any players to Black's cause."
and gives no analysis. I was also unable to find any games with these moves or any other source. Does anybody know why Qa4 is most populair? or is 8.0-0-0!? maybe 8.0-0-0?! and 8.Rd1!?