TY  - DATA
AU  - Jackson, Robert John Victor.
TI  - Canonical differential operators and lower-order symbols
T2  - Memoirs of the American Mathematical Society, 
SN  - 9780821899342 (online)
PY  - 1973///
CY  - Providence
PB  - American Mathematical Society
UR  - http://www.ams.org/memo/0135
ER  -