[Event "IBM"]
[Site "Amsterdam"]
[Date "1971.07.16"]
[Round "4"]
[White "Bobotsov, Milko Georgiev"]
[Black "Ree, Hans"]
[Result "1/2-1/2"]

1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 dxc4 5. e3 b5 6. a4 b4 7. Nb1 Ba6 8. Be2 e6 9. O-O Be7 10. Nbd2 O-O 11. Bxc4 Bxc4 12. Nxc4 c5 13. Qe2 Nc6 14. dxc5 Bxc5 15. b3 Qe7 16. Bb2 Rfd8 17. Rad1 Nd5 18. Qc2 Rac8 19. Rd2 Nb6 20. Rfd1 Nxc4 21. Qxc4 Rxd2 22. Rxd2 Na5 23. Qa6 Nb7 24. g3 1/2-1/2