He cites only Kupreichik-Beliavsky, Leningrad 1974
[Event "URS-ch42"]
[Site "Leningrad"]
[Date "1974.??.??"]
[Round "5"]
[White "Kupreichik, Viktor D"]
[Black "Beliavsky, Alexander G"]
[Result "0-1"]
[WhiteElo "2460"]
[BlackElo "2460"]
[ECO "B99"]
[EventDate "1974.11.30"]
[EventType "tourn"]
[EventRounds "15"]
[EventCountry "URS"]
[EventCategory "12"]
[Source "ChessBase"]
[SourceDate "1999.07.01"]
1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6.Bg5 e6 7.f4 Be7 8.Qf3 Qc7
9.O-O-O Nbd7 10.Qg3 h6 11.Bh4 g5 12.fxg5 Nh5 13.Qe3 Qc5 14.Kb1 hxg5 15.Bf2
Ne5 16.Qd2 Qc7 17.Nf3 Nxf3 18.gxf3 Bd7 19.Rg1 O-O-O 20.Be3 f6 21.Qf2 Nf4
22.Bxf4 gxf4 23.Rg4 Qc5 24.Qd2 Qe5 25.h3 Be8 26.Rxf4 Bh5 27.Be2 Kb8 28.Rg1
Rc8 29.a3 Bd8 30.Qc1 Bb6 31.Rf1 Bd4 32.Bd3 Bxc3 33.bxc3 Rxc3 34.Rh4 Qg5
35.Qe1 Qc5 36.Qc1 Rc8 37.Qb2 Rc6 38.e5 a5 39.Ka2 Rb6 40.Qc1 Qd5+ 41.Ka1
Qxe5 42.Ka2 Qd5+ 43.Ka1 Bf7 44.Rh7 e5 45.Rxf7 Qxf7 46.h4 Qe8 47.Rh1 Qa4
48.Ka2 Rbb3 0-1
when I can't figure out why Kupreichik didn't take the exchange with 22. Bb6
as Black doesn't have enough even though his bishops look nice after
22...Rxh2 (it's probably better to not take the pawn, keeping an extra pair of rooks on the board but white is certainly to be favored anyway) 23.Rg2 Rxg2 24.Bxg2 Qc6 25.Bxd8 Bxd8 26. Bf1
Your 20. Bd4 move should be similar and also favor white.