function letter() {
	window.open('subscribe.htm', 'popup' ,'resizable=yes,width=480,height=520,status=no,location=no,toolbar=no,menubar=no,scrollbars=yes');
}

function video() {
	window.open('video-about-Si/appassionata-si.html', 'popup' ,'resizable=yes,width=800,height=590,status=no,location=no,toolbar=no,menubar=no,scrollbars=yes');
}