4Chronology and Style in the Early Works : A Background for the Orgel-Buchlein , Christian wolff, in Bach:Essavs on His Life and Music Harward University Press, 1991.
5BACH Chapter 4 -Organ music, Malcolm Boyd. J. M. Dent & Sons Ltd. London&Melboure 1986.
6Big Conception for a little Book, Tim Smith, 1996,on Internet.
