TY  - JOUR
AU  - Harris, Douglas
TI  - Extension Closed and Cluster Closed Subspaces
JO  - Canadian journal of mathematics
PY  - 1972
SP  - 1132
EP  - 1136
VL  - 24
IS  - 6
UR  - http://geodesic.mathdoc.fr/articles/10.4153/CJM-1972-119-8/
DO  - 10.4153/CJM-1972-119-8
ID  - 10_4153_CJM_1972_119_8
ER  -