function withdrawBonus() onlyBonusOwner {
        if(now>finalTimestampOfBonusPeriod) {
            var bonusValue = ownedBonus[msg.sender];
            ownedBonus[msg.sender] = 0;
            BonusWithdrawn(msg.sender, bonusValue);
            msg.sender.transfer(bonusValue);
        }
    }