The most influential writing on the work today is William Kinderman's "Beethoven's Diabelli Variations", which begins by carefully tracing the development of the work through various Beethoven sketchbooks. Of great significance, according to Kinderman, is the discovery that a few crucial variations were added in the final stage of composition, 1822–23 and inserted at important turning-points in the series. A careful study of these late additions reveals that they stand out from the others by having in common a return to, and special emphasis on, the melodic outline of Diabelli's waltz, in the mode of parody.