void removeChild (Node child)
    {
        if (_occurs_ == child)
        {
            _occurs_ = null;

            return;
        }

        if (_occursTo_ == child)
        {
            _occursTo_ = null;

            return;
        }

        if (_number_ == child)
        {
            _number_ = null;

            return;
        }

        if (_times_ == child)
        {
            _times_ = null;

            return;
        }

        if (_depending_ == child)
        {
            _depending_ = null;

            return;
        }

        if (_on_ == child)
        {
            _on_ = null;

            return;
        }

        if (_dataName_ == child)
        {
            _dataName_ = null;

            return;
        }
    }