http://gigazine.net/index.php?/news/comments/20080612_jigsaw_puzzles_geographic/

http://booklog.kinokuniya.co.jp/london/archives/2008/06/post_14.html

http://www.toyokeizai.co.jp/CGI/kensaku/syousai.cgi?isbn=55612-5

http://gigazine.net/index.php?/news/comments/20080614_milimesi/

http://www.chunichi.co.jp/article/technology/science/CK2008052702000180.html

http://chiquita.blog17.fc2.com/blog-entry-3293.html

http://headlines.yahoo.co.jp/hl?a=20080614-00000920-san-soci

http://response.jp/issue/2008/0613/article110473_1.html