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b. 139

composition: Op. 50 No. 3, Mazurka in C♯ minor

..

We add a cautionary  before b1 in the main text.

category imprint: Editorial revisions

b. 140

composition: Op. 50 No. 3, Mazurka in C♯ minor

e-a in AI, AF, GEEE

e-c1 in FE

..

In the main text we give the sixth of FE, introduced by Chopin in the last stage of proofreading instead of a fourth, present in the remaining sources. One can see traces of a correction in the copies of FE.

category imprint: Differences between sources; Corrections & alterations

issues: Accompaniment changes , Authentic corrections of FE

b. 140

composition: Op. 50 No. 3, Mazurka in C♯ minor

a1-e1-d1 in AI

b1-a1-e1 in AF (→FEEE) & GE

..

The version of AI is the initial one and was then changed, most probably at the time when the R.H. top voice was being added.

category imprint: Differences between sources; Corrections & alterations

issues: Main-line changes

b. 144

composition: Op. 50 No. 3, Mazurka in C♯ minor

..

In the main text we add a cautionary  before a.

category imprint: Editorial revisions

b. 149-151

composition: Op. 50 No. 3, Mazurka in C♯ minor

..

In b. 149 and 151 the autographs are devoid of cautionary accidentals. In the first stage of proofreading of FE (→EE) a  was added before b in b. 151; the accidental is also present in GE. In the second stage of proofreading of FE before b was also added in b. 149; moreover, a  was repeated before the R.H. b note on the 3rd beat of the bar.
We include both naturals in the main text. 

category imprint: Differences between sources

issues: Cautionary accidentals , Authentic corrections of FE , FE revisions