Tertium Organum, the third canon of thought : a key to the enigmas of the world - Uspenskiĭ, P. D. (Petr Demʹi͡anovich), 1878-1947; Bessaraboff, Nicholas, 1894-1973; Bragdon, Claude Fayette, 1866-1946 (London : Kegan Paul, Trench, Trubner, 1926)