Audio Companion: Part II, pages 24-26
Chapter 2: The Free Use of Quarter Tones
§57 Expressive unison, quartertonal second
§57 Expressive unison, extension to groups
§57 Inversion and substitution for the octave
§57 Parallel motion
§57 Chords composed of twenty-four notes
§58 Polytonality in quarter tones
§59 Bi-atonality