Norman D. Cook has some very nice papers about harmony and tri-chords that make the case that intervals are not what matters when it comes to characterizing mor

Norman D. Cook has some very nice papers about harmony and tri-chords that make the case that intervals are not what matters when it comes to characterizing more complex harmonies: http://www.res.kutc.kansai-u.ac.jp/~cook/ http://www.res.kutc.kansai-u.ac.jp/~cook/