Adding a link to a CSS file to the document

From Joomla! Documentation

To add a link to a CSS file to the document, you could use:

$doc =& JFactory::getDocument();
$href = 'index.php/other/css/mycss.css'; 
$attribs = array('type' => 'text/css'); 
$doc->addHeadLink( $href, 'stylesheet', 'rel', $attribs );

When the document is rendered this will produce the following in the HTML <head> section:

<link href="/index.php/other/css/mycss.css" rel="stylesheet" type="text/css" />

This is an alternative to using JDocument->addStyleSheet.