TY  - JOUR
AU  - Arthur W. Apter
TI  - $L$-like Combinatorial Principles  and Level by Level Equivalence
JO  - Bulletin of the Polish Academy of Sciences. Mathematics
PY  - 2009
SP  - 199
EP  - 207
VL  - 57
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/articles/10.4064/ba57-3-2/
DO  - 10.4064/ba57-3-2
LA  - en
ID  - 10_4064_ba57_3_2
ER  -