External links
Shodokan links
Shodokan books
Aikido: Tradition and the Competitive Edge Fumiaki Shishida, Tetsuro Nariyama - Shodokan Publishing USA (March 2002).
Aikido and Randori: Reconciliation of Two Opposing Forces Scott Allbright - The Crowood Press (May 31, 2002)
Principles of Aikido (Thorsons Principles Series). Paul John Wildish - Harper Collins (October 5, 1998)
Understanding Shodokan Aikido Sean Masaki Flynn - Shodokan Publishing USA (January 2002)
Background information
Aiki web forum a repository, dissemination point and bulletin board for Aikido information.
Omotokyo As Ueshiba Morihei, the founder of Aikido, said that Aikido comes from his belief in the Omotokyo religion, this site maybe of interest.