TY  - JOUR
AU  - Pakula, Lewis
AU  - Schwartzman, Sol
TI  - Independence for Sets of Topological Spheres
JO  - Canadian mathematical bulletin
PY  - 1991
SP  - 520
EP  - 524
VL  - 34
IS  - 4
UR  - http://geodesic.mathdoc.fr/articles/10.4153/CMB-1991-082-1/
DO  - 10.4153/CMB-1991-082-1
ID  - 10_4153_CMB_1991_082_1
ER  -