TY  - DATA
AU  - Figueiredo, Leila
TI  - Calculus of principally twisted vertex operators 
T2  - Memoirs of the American Mathematical Society, 
SN  - 9781470407872 (online)
PY  - 1987///
CY  - Providence, R.I., USA
PB  - American Mathematical Society
UR  - http://www.ams.org/memo/0371
ER  -