The 
raising e
to e added by GE (→FE,EE,IE) resulted from a routine revision, locally adjusting the L.H. chord sound to the g1-e2 sixth in the R.H. (cf. a similar revision in GE1 in the Etude in A minor, Op. 10 No. 2, bar 7). In fact, despite the temporary presence of the key of C major in bars 75-77, the general key is still C minor (from bar 73 on), while e2 is a transitory note. Therefore, in the main text we leave e, present in A, adding a cautionary 
to this note to avoid any misunderstanding.
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category imprint: Differences between sources
issues: GE revisions
notation: Pitch