@article{10_4064_fm_78_1_37_42,
     author = {Richard O'Malley},
     title = {Strong essential cluster sets.},
     journal = {Fundamenta Mathematicae},
     pages = {37--42},
     publisher = {mathdoc},
     volume = {78},
     number = {1},
     year = {1973},
     doi = {10.4064/fm-78-1-37-42},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-78-1-37-42/}
}