function loadFile($filename)
    {
        if (file_exists($filename)) {
            if (($this->content = @file_get_contents($filename)) === false) {
                throw new BibtexException('Could not open file ' . $filename);
            } else {
                $this->_pos = 0;
                $this->_oldpos = 0;
                return true;
            }
        } else {
            throw new BibtexException('Could not find file ' . $filename);
        }
    }