private function _show_previous() {

        $output = '';

        // if "always_show_navigation" is TRUE or
        // if the number of total pages available is greater than the number of selectable pages
        // it means we can show the "previous page" link
        if ($this->_properties['always_show_navigation'] || $this->_properties['total_pages'] > $this->_properties['selectable_pages']) {

            // CSS classes to be applied to the list item, if any
            $css_classes = isset($this->_properties['css_classes']['list_item']) && $this->_properties['css_classes']['list_item'] != '' ? array(trim($this->_properties['css_classes']['list_item'])) : array();

            // if we're on the first page, the link is disabled
            if ($this->_properties['page'] == 1) $css_classes[] = 'disabled';

            // generate markup
            $output = '<li' .

                // add CSS classes to the list item, if necessary
                (!empty($css_classes) ? ' class="' . implode(' ', $css_classes) . '"' : '') . '><a href="' .

                // the href is different if we're on the first page
                ($this->_properties['page'] == 1 ? 'javascript:void(0)' : $this->_build_uri($this->_properties['page'] - 1)) . '"' .

                // add CSS classes to the anchor, if necessary
                (isset($this->_properties['css_classes']['anchor']) && $this->_properties['css_classes']['anchor'] != '' ? ' class="' . trim($this->_properties['css_classes']['anchor']) . '"' : '') .

                // good for SEO
                // http://googlewebmastercentral.blogspot.de/2011/09/pagination-with-relnext-and-relprev.html
                ' rel="prev">' .

                ($this->_properties['reverse'] ? $this->_properties['next'] : $this->_properties['previous']) . '</a></li>';

        }

        // return the resulting string
        return $output;

    }