http://www.boutell.com/gd/
http://www.systemj.com/index.php?page=php&cat=gd1
http://www15.tok2.com/home/masato/3-6.html
http://www.pat.hi-ho.ne.jp/dimension/sample/sample_others_gd.shtml
http://www51.tok2.com/home/coop/php4/how2use_GD.html
http://www.hotwired.co.jp/webmonkey/2001/36/index4a.html
http://www.h2.dion.ne.jp/~yamaga/gd-j/