var randomnumber;
		var x;
		var books;
		
		books = 4;
		
		randomnumber = Math.floor(Math.random() * books);
		randomnumber = randomnumber + 1;
		
		switch(randomnumber)
			{
			case 1:
				document.write('<iframe src="http://www.trifind.net/b/pigman/2009/3.html" width=130 height=160 frameborder=0 scrolling=no marginwidth=0 marginheight=0></iframe>');
				break;
			case 2:
				document.write('<a href="http://www.midwesttriathloncoaching.com/" target="_blank"><img src="http://www.trifind.net/b/kc-tri-coach/side.jpg"');
				document.write(' border="0"');
				document.write(' alt="Multi Sport Training"></a>');
				break;
			case 3:
				document.write('<iframe src="http://www.trifind.net/b/best-of-the-us/2010/side/MO1.html" width=130 height=130 frameborder=0 scrolling=no marginwidth=0 marginheight=0></iframe>');
				break;
			case 4:
				document.write('<iframe src="http://www.trifind.net/b/best-of-the-us/2010/side/MO2.html" width=130 height=130 frameborder=0 scrolling=no marginwidth=0 marginheight=0></iframe>');
				break;
			}