This is the third edition of “Principles of Time and Space: New Octonions
and Relativity” (ISBN 978-4-9906664-0-8) published in Japanese in 2012.
Download is free for personal use. This book (ISBN 978-4-9906664-2-2) can
be purchased only at Amazon. co. jp
(www.amazon.co.jp). The author's e-mail address is email@example.com.