All other extant manuscript copies of the score date from at least several decades later: some of these, written in the 19th century, are related with each other in that they have similar solutions to the defects in the Ringk manuscript. Whether these derive from an earlier manuscript independent from Ringk's (possibly in the C. P. E. Bach/Johann Friedrich Agricola/Johann Kirnberger circle) is debated by scholars. These near-identical 19th-century copies, the version Felix Mendelssohn knew, use the treble clef and a separate stave for the pedal. In general, the later copies show a less excessive use of fermatas in the opening measures and are more correct in making the note values fit the measures, but that may as well be from polishing a defective source as from deriving from a cleaner earlier source. In the later copies the work is named for instance "Adagio" and "Fuga" (for the respective parts of the work), or "Toccata" for the work as a whole.