Yeo, A. (2007). Trig or treat: An encyclopedia of trigonometric identity proofs (TIPs), intellectually challenging games. World Scientific Pub..
Chicago-referens (17:e uppl.)Yeo, Adrian. Trig or Treat: An Encyclopedia of Trigonometric Identity Proofs (TIPs), Intellectually Challenging Games. Singapore: World Scientific Pub., 2007.
MLA-referens (9:e uppl.)Yeo, Adrian. Trig or Treat: An Encyclopedia of Trigonometric Identity Proofs (TIPs), Intellectually Challenging Games. World Scientific Pub., 2007.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.