TY  - JOUR
AU  - Feferman, Solomon
TI  - Persistent and invariant formulas for outer extensions
JO  - Compositio Mathematica
PY  - 1968
SP  - 29
EP  - 52
VL  - 20
PB  - Wolters-Noordhoff Publishing
UR  - http://www.numdam.org/item/CM_1968__20__29_0/
LA  - en
ID  - CM_1968__20__29_0
ER  -