@article{10_4064_cm_37_2_255_261,
     author = {M. J. Evans and P. D. Humke},
     title = {On qualitative cluster sets},
     journal = {Colloquium Mathematicum},
     pages = {255--261},
     publisher = {mathdoc},
     volume = {37},
     number = {2},
     year = {1971},
     doi = {10.4064/cm-37-2-255-261},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-37-2-255-261/}
}