the Popular Style: The Antecedents of Twentieth-Century Popular Music. Oxford: Clarendon Press. . Nettles, Barrie & Graf, Richard (1997). The Chord Scale Theory and Jazz Harmony. Advance Music, Further reading Prout, Ebenezer, Harmony, its Theory and Practice (1889, revised 1903) External links Chord Geometry – Graphical Analysis of Harmony Tool Concepts in aesthetics Sound Psychoacoustics Consonance and dissonance