hoshi911: I think w-G18, b-E16, w-F19 should also be correct. Black has to capture three white stones with b-J17 or b-K16 (otherwise after b-F17 his enclosed group will be captured with w-F16). Hence, after b-J17 or b-K16, White plays w-F17 and the result is the same as in the provided answer.
Ivan Detkov: I disagree with your comment. White made an extra move here (F1) and this move is just losing sente.
OK, I can see your point. Thanks