function doEndnotes( $id ) {

		if ( ! isset( $this->endnotes[ $id ] ) || ! count( $this->endnotes[ $id ] ) ) {
			return '';
		}

		$e = '<div class="endnotes">';
		$e .= '<hr />';
		$e .= '<h3>' . __( 'Notes', 'pressbooks' ) . '</h3>';
		$e .= '<ol>';
		foreach ( $this->endnotes[ $id ] as $endnote ) {
			$e .= "<li><span>$endnote</span></li>";
		}
		$e .= '</ol></div>';

		return $e;
	}