I'm not sure if this is Falck 30 or Falck 'nv'30 (I think nv is something like appendix?) - in the recording I have of this work on Harmonia Mundi (Christophe Rousset, hpd) it's given as nv 30 but that could well be wrong? Eric 02:16, 7 September 2010 (UTC)
I think nv means new version. I found at google books the original work catalogue from Martin Falck with short excerpts of the score. And he named the piece as Falck 30. Maybe someone actualized the work catalogue and used nv to mark that it is more actual than Falck's catalogue. Tobias 23:38, 14 October 2010 (UTC)
This is Fk 30. Actually, "n.v" stands for "nicht verzeichnete" (not catalogued, in this case by Falck). Fk n.v. 30 is the keyboard part of a sonata in F for kb, vn, and vc that is actually by J. C. Bach.
The present score contains numerous inaccuracies, perhaps as a result of having been transcribed from a recording. A more accurate score is online at http://www.wagner.edu/faculty/dschulenberg/sites/wagner.edu.faculty.dschulenberg/files/wfb/F25-30.pdf.