TY  - BOOK
AU  - Henle, James M.
TI  - An outline of set theory
T2  - Problem books in mathematics
SN  - 3540963685
U1  - 511.322 
PY  - 1986///
CY  - New York: 
PB  - Springer Verlag, 
KW  - Math
KW  - Natural numbers
KW  - Ordinals
KW  - Rationals
ER  -