TY  - JOUR
AU  - J. Płonka
TI  - On k-closure operators in graphs
JO  - Colloquium Mathematicum
PY  - 1980
SP  - 373
EP  - 381
VL  - 43
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/articles/10.4064/cm-43-2-373-381/
DO  - 10.4064/cm-43-2-373-381
LA  - en
ID  - 10_4064_cm_43_2_373_381
ER  -