@article{Kleinbergetal:jacm04,
 author = {Kleinberg, Jon and Papadimitriou, Christos and Raghavan, Prabhakar},
 title = {Segmentation Problems},
 journal = {Journal of the {ACM}},
 volume = {51},
 issue = {2},
 year = {2004},
 pages = {263--280},
 keywords = {clustering, approximation algorithms, data mining, market segmentation},
}