ISBN 9780394513508 books & textbook
Tertium Organum: The Third Canon of Thought, a Key to the Enigmas of the World
P. D Ouspensky E. Kadloubovsky Nicholas Bessaraboff Claude Bragdon
Alfred A. Knopf /1981T Hardcover / 298 Pages
isbn-10: 0394513509 / isbn-13: 9780394513508