Vries, Gerard de. Nabokov’s Pale Fire and the Last Works of J. S. Bach. 2006

The evidence is solid enough to argue that Pale Fire's structure can/should be seen in the light of a fugue by Bach: a theme repeated in variegated forms. For example, in the Musical Offer (an elaboration of the royal theme given by Frederick the Great to Bach, and as difficult to recognize as Kinbote's theme in Shade's poem) one single melody results in a fugue of which the different voices are allotted to a flute, a violin and a harpsichord. Likewise is the theme of Pale Fire given to three "voices", Shade, Kinbote and Gradus. The implication of this is that it doesn't make much sense to look for a hierarchy between these voices, in other words selecting Kinbote or Shade as the author of the whole is in vain.