graph TD O["O (Orgel-Büchlein: autograph fair copy)"] --> W1["[W¹] (autograph composing score or draft, probably from the Weimar period, but possibly to be dated in the Leipzig years)"] W1 --> W2["[W²] (apograph fair copy, perhaps written by Altnikol)"] W2 --> V1["[V¹] (apograph 'dictation copy')"] W2 --> W3["[W³] (apograph printer's copy in open score)

After Bach's death:"] V1 --> V2["V² (P 271: fair copy by Anon. 12)"] W3 --> W4["W⁴ (printing in four-part scoring, contained in the Art of Fugue)"]