The previous page is sending you to http://webcache.googleusercontent.com/search?q=cache:kZJ5CJZz9VsJ:http://www.freepatentsonline.com/article/Australian-Senior-Mathematics-Journal/164525635.html%2BTOROID+PHI+MATHEMATICS&hl=es-419&gbv=2&&ct=clnk.

 If you do not want to visit that page, you can return to the previous page.