@article{700838,
     title = {The compactness operator in general topology},
     booktitle = {General Topology and its Relations to Modern Analysis and Algebra},
     series = {GDML\_Books},
     publisher = {Academia Publishing House of the Czechoslovak Academy of Sciences},
     address = {Praha},
     year = {1967},
     pages = {161-163},
     mrnumber = {MR0232332},
     zbl = {0165.25301},
     url = {http://dml.mathdoc.fr/item/700838}
}

de Groot, J. The compactness operator in general topology, dans General Topology and its Relations to Modern Analysis and Algebra, GDML_Books,  (1967), pp. 161-163. http://gdmltest.u-ga.fr/item/700838/