TY  - DATA
AU  - Epstein, Richard L.
TI  - Initial segments of degrees below 0' 
T2  - Memoirs of the American Mathematical Society, 
SN  - 9781470406486 (online)
PY  - 1981///
CY  - Providence, R.I.
PB  - American Mathematical Society
UR  - http://www.ams.org/memo/0241
ER  -