How to keep my pages from beein cached

My web pages for www.missionnicaragua.net keep getting cached and for very long times. How do I code my pages to keep that from happening?

 

This may help:

http://www.htmlgoodies.com/beyond/reference/article.php/3472881

 

From php manual about header function:

header("Expires: Mon, 26 Jul 1997 05:00:00 GMT"); // Date in the past
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
// always modified
header("Cache-Control: no-store, no-cache, must-revalidate"); // HTTP/1.1
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache"); // HTTP/1.0


This should do the trick.