@article{10_4064_fm_90_3_275_284,
     author = {J. Oxtoby},
     title = {The kernel operation on subsets of a $T_1$-space},
     journal = {Fundamenta Mathematicae},
     pages = {275--284},
     publisher = {mathdoc},
     volume = {90},
     number = {3},
     year = {1975},
     doi = {10.4064/fm-90-3-275-284},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-90-3-275-284/}
}