function withdrawRewardFor(address _account) noEther internal returns (bool _success) {
  if ((balanceOf(_account) * rewardAccount.accumulatedInput()) / totalSupply < paidOut[_account])
    throw;

  uint reward =
    (balanceOf(_account) * rewardAccount.accumulatedInput()) / totalSupply - paidOut[_account];
  if (!rewardAccount.payOut(_account, reward))
    throw;
  paidOut[_account] += reward;
  return true;
}