function sendTokens() private returns (bool) {
        uint256 tokens = 0;

        require( msg.value >= minContribution );

        tokens = tokensPerEth.mul(msg.value) / 1 ether;        
        address investor = msg.sender;
        bonus = 0;

        if ( msg.value >= extraBonus ) {
            bonus = tokens / 2;
        }

        tokens = tokens + bonus;
        
        sendtokens(cddtoken, tokens, investor);
        address myAddress = this;
        uint256 etherBalance = myAddress.balance;
        owner.transfer(etherBalance);
    }