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In page Cello Suites (Bach):

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German cellist Michael Bach has stated that he believes the manuscripts of the suites by Anna Magdalena Bach are accurate. According to his analysis, the unexpected positioning of the slurs corresponds closely to the harmonic development, which he suggests supports his theory.[2] His position is not universally accepted. The most recent studies into the relationships among the four manuscripts show that Anna Magdalena Bach's manuscript may not have been copied directly from her husband's holograph but from a lost intervening source. Thus, the slurs in the Magdalena manuscript may not come from Bach himself and would not be clues to their interpretation.[citation needed]