- Interview with William Segal - National Public Radio (NPR) interview with William Segal, a pupil of Gurdjieff and others, in Real Audio.
- KHA Records' Gurdjieff "Hidden Sources" - Information about and online ordering of Alessandra Celletti's interpretations of the music of Gurdjieff and De Hartmann.
- The Musical Octave, Part I, From a Mathematical, Acoustic Point of View. - Thomas Váczy Hightower's "brief resume of about 150 pages I have previously written in the Danish language of a study of musical scales, regarded as a sub octave of the cosmic octave; also called The Ray of Creation. I am aware of taking liberties with considering music or standing sound waves as a part of the "Ray of Creation" because I have not directly found in Gurdjieff/Ouspensky/Rodney Collin workbooks that the musical octaves are inner octaves in the great display of octaves within octaves as the cosmic octave consists of."
- The Musical Octave, Part II, The Metaphysical Properties of Sound and Music. - Thomas Váczy Hightower's "Metaphysics means a level above the physical, which applies to matter. So this little treatise is about inaudible sound, about the silence underneath the music; the silence deep inside oneself where God resides, that is my focus."
- Triangle Records - Online ordering from publishers of a recording of "The Music of Gurdjieff/De Hartmann".
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