http://www.scei.co.jp/products/psp.html
http://www.watch.impress.co.jp/av/docs/20041212/psp.htm
http://kin.naver.com/open100/entry.php?docid=165557 (한글)
http://blog.naver.com/daum8879.do?Redirect=Log&logNo=120008450668 (한글)