TY  - JOUR
AU  - J.I. FRIEDMAN
TI  - Proper Classes as Members of Extended Sets.
JO  - Mathematische Annalen
PY  - 1969
SP  - 232
EP  - 240
VL  - 183
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MAN_1969__183_161893/
ID  - MAN_1969__183_161893
ER  -