Christopher Collins, Gerald Penn, M. Sheelagh T. Carpendale. Bubble Sets: Revealing Set Relations with Isocontours over Existing Visualizations. IEEE Trans. Vis. Comput. Graph., 15(6):1009-1016, 2009. [doi]
@article{CollinsPC09,
title = {Bubble Sets: Revealing Set Relations with Isocontours over Existing Visualizations},
author = {Christopher Collins and Gerald Penn and M. Sheelagh T. Carpendale},
year = {2009},
doi = {10.1109/TVCG.2009.122},
url = {http://dx.doi.org/10.1109/TVCG.2009.122},
researchr = {https://researchr.org/publication/CollinsPC09},
cites = {0},
citedby = {0},
journal = {IEEE Trans. Vis. Comput. Graph.},
volume = {15},
number = {6},
pages = {1009-1016},
}