Reference guides
Every key, with nothing spelt wrong: scales, chords, keys and intervals.
Scales in all twelve keysPrice to be setDiatonic chords in every key, major and minor, with functionsPrice to be setCircle of fifths — poster and pocket cardPrice to be setKey signaturesPrice to be setIntervals — name, semitones, inversion, an example on the staffPrice to be setChord formulas, from triads to sevenths and tensionsPrice to be setReading chord symbols — and how each is written in other traditionsPrice to be setNote names: C-D-E ↔ do-re-mi, and accidentalsFreeNote and rest values, and time signaturesPrice to be setCadences — authentic, plagal, deceptive, halfPrice to be setRoman numeral analysisPrice to be setChords by scale degree (I, ii, V…) in every key, for transposing on the spotPrice to be setCapo and transposition chartPrice to be setSecondary dominants in every keyPrice to be set