TY  - JOUR
AU  - Arthur W. Apter
TI  - Mixed Levels of Indestructibility
JO  - Bulletin of the Polish Academy of Sciences. Mathematics
PY  - 2015
SP  - 113
EP  - 122
VL  - 63
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/articles/10.4064/ba63-2-2/
DO  - 10.4064/ba63-2-2
LA  - en
ID  - 10_4064_ba63_2_2
ER  -