Frr me too, i’ve never read them but they seem interesting
The A minor chord i7 is the A min 7 chord, and contains the notes A, C, E, and G. This tonic 7th chords root / starting note is the 1st note (or scale degree) of the A natural minor scale. The roman numeral for number 1 is 'i', and is used to indicate this is the 1st chord in the scale.