January 1, 2019
Document on fifths
Author unknown
Document on The Spiral of fifths and the Pythagorean comma
Document on Circle of fifths as interval calculator
Document on Geometry of the full circle of fifths
Document on Advanced seventh chords
Document on Key signatures in order of accidentals
Document on Advanced scales
Document on Map of keys
Document on Triads
Document on Traditional classification of chords in consonant and dissonant