TY  - JOUR
AU  - Martin, Harold W.
TI  - Derived Subspaces of Metric Spaces
JO  - Canadian mathematical bulletin
PY  - 1980
SP  - 465
EP  - 467
VL  - 23
IS  - 4
UR  - http://geodesic.mathdoc.fr/articles/10.4153/CMB-1980-070-0/
DO  - 10.4153/CMB-1980-070-0
ID  - 10_4153_CMB_1980_070_0
ER  -