TY  - DATA
AU  - Essen, A. R. P. van den
AU  - Levelt, A. H. M.
TI  - Irregular singularities in several variables 
T2  - Memoirs of the American Mathematical Society, 
SN  - 9781470406806 (online)
PY  - 1982///
CY  - Providence, R.I.
PB  - American Mathematical Society
UR  - http://www.ams.org/memo/0270
ER  -