TY  - SER
AU  - Werf,Hendrik Van Der
AU  - Zijlstra,A.Marcel J.
TI  - On "Abbot Helisachar's Antiphoner" by Keeneth Levy, Summer 1995
PY  - 1997///
CY  - [Richmond (Va) 
PB  - American Musicological Society]
ER  -